Travelin’ light is the only way to fly.
What To Pack It In
Business Travel Bags
For business travel in urban locations, the best solution is a bag specifically designed for optimal packing. Ideally, this includes three main (full-length and full-width) compartments, with the zippers on at least two of them designed to completely free up three sides of the bag (permitting them to be opened flat for packing, and also allowing access to the bag when it is sandwiched in a luggage rack or aircraft overhead bin); the compartments should have internal tie-down straps, so their contents can be prevented from shifting (and thus wrinkling). The bag should be constructed of quality components, including strong fittings to accommodate a shoulder strap.
A Recommended Business Bag
Almost from the inception of this Web site in 1996, I have bemoaned the lack of truly exceptional business-style carry-on bags. At the time, I used the excellent Boyt model LG336 ("3-Zip Air-Bus Carry-On"), but neither it nor any suitable replacement was available for many years (since the bankruptcy of the original Boyt company). 
In 2004, however, a Montana-based maker of rugged "adventure" luggage responded to my frustration, asking if I would like to help them design the "ultimate carry-on bag" for business travellers. I happily agreed, and you can view their resulting product at right: the Red Oxx "Air Boss" (in one of its dozen colours, including basic business black). It measures 22×14×8" (56×36×20cm), weighs 3 pounds (1.36kg) and features (in addition to the three main compartments, all with wrap-around zippers) two outside zippered pockets (one full length, and a narrow one for passport, ticket envelopes, chequebook, and the like), an outside sleeve pocket, and tie-downs in two of the main sections (they're omitted from the centre section to facilitate sliding laptops and such in and out of a heavily packed bag). Construction is 1000-weight urethane-coated Cordura nylon fabric, with #10 YKK chain zippers throughout, mil-spec handle snaps, and bomb-proof D-rings for the shoulder strap (included is the exemplary "Claw" strap and a heavy-duty luggage tag). All seams are double-stitched and bound with #92 bonded SolarMax nylon thread. The discreet use of inter-compartment closed-cell foam padding gives the bag some structure for packing purposes, without compromising the flexibility necessary to get the bag into tight overhead compartments. It lists for USD$285.
Air Boss users should know that it was designed to be carried with the passport and open sleeve pockets nearer the body. The (main) compartment on this side should also be the primary storage space for clothing, allowing it not only to protect items in the centre of the bag, but also cushion the bag's contact with your hip.
I hasten to add that my involvement with the creation of the above bag was a labour of love, not commerce. Other than getting an Air Boss of my own out of the collaboration, I received no compensation for my design contributions, and I obtain no monetary benefit from the sale of the bags. I recommend this bag because it is the closest approximation (that I'm aware of) to my ideal business bag — being, after all, primarily my own design — and for no other reason.
Business travellers who are willing to sacrifice some interior space for improved carrying capability might also consider dual-purpose travel bags. And a day bag can be a useful adjunct to a travel arsenal, particularly when one is forced to check luggage.
Thoughts on the Mini Boss Red Oxx also sells a bag dubbed the "Mini Boss", a sort of miniature version of the "Air Boss". It's not really appropriate for typical business travel, as its length and width are too short to accommodate properly-packed business attire (for average-sized men, anyway). For other travel situations, it's primarily a consideration of capacity.
The problem with very small bags is that their volume (which is a multiple of three separate dimensions) decreases surprisingly rapidly. The standard Air Boss is only $20 more expensive (and 8 oz / 227g heavier) than the Mini, but provides 66% more packing space ... almost 1000 cubic inches (16 liters)! So for most business travel, I would definitely recommend the Air Boss.
Shoulder Straps
For most business travellers, a single shoulder strap is the most common carrying method: it's convenient, effective, and leaves both your hands free for more important tasks than lugging your belongings. Unless your shoulders are horizontal, well padded, and non-slip, consider buying a better strap than those supplied with most bags. If it doesn't cling tenaciously to your shoulder, you will constantly be raising (hunching) that shoulder and tugging on the strap as you move about, both of which will prove quite uncomfortable — even painful — over all but the briefest periods of time. Here are some particularly good solutions:
My personal favourite is an outstanding high-tech design from Montana's Quake Industries: "The Claw", a rugged, supple (to −40°) shoulder strap with a moulded-in, non-slip, U.V. stabilized (no fading or cracking), polymer-rubber-based pad that also provides about an inch of built-in, shock-absorbing stretch. This provides what is easily the best "grip" of any strap I've ever tested. It's adjustable in length from 19" (48cm) to 58" (147cm). Red Oxx sells it for USD$30, but adds heavy metal snaphooks, unfortunately almost doubling the weight to 9 oz. (255g). The sufficiently motivated will eliminate 4.2 oz. (119g) of this by replacing the snaphooks with strong nylon versions, such as this one from Duraflex.- Tom Bihn sells the "Absolute Shoulder Strap" (USD$30 with metal clips), adjustable in length from 20" (51cm) to 52" (132cm). Its combination of soft, durable neoprene pad with comfortable stretch backing provide increased shock-absorbing action, thus making it slightly more comfortable with heavier loads, but it's not as slip-proof (which I find to be more important) as The Claw.
- If you have a bag strap that can't be replaced for some reason (perhaps it's permanently affixed, or has an unusual attachment method), it may be possible to augment it with one of those dense rubber wedge-shaped shoulder pads used by U.S. Post Office letter carriers: Domke makes them in a style that allows easy attachment to a standard carrying strap.
Passing the strap over your head, messenger style, to rest on the shoulder further from the bag, is easier on your back (I know, it looks a bit dorky, so you probably won't do it, but it is the better choice).
If you're using a curved strap (like newer versions of Bihn's "Absolute Shoulder Strap"), appreciate that there is a right and a wrong way to deploy such a design. So if you want to look like you know what you're doing (and I see plenty of travellers who don't), position the strap such that the concave side (the shorter one) is closer to the bag.
If none of this improves your travel comfort, consider that your bag may simply be too heavy (and recall that the goal is to travel lightly). If that's not the problem — your bag is under 10kg (22 lb) and you're still suffering — you may just not be physically equipped for a single-shoulder carry: consider the improved carrying capability of double ("backpack"-style) shoulder straps. Those who don't categorically rule out this slightly-less-macho look will find at least a few business-friendly bags with this feature. When using one, pack the heaviest items closest to your back, and keep the bottom of the bag above your waist when carrying it.
Incidentally, if you're ever required to submit your bag for weighing, remember to remove the shoulder strap before doing so; it may keep you from exceeding some weight limit.
Luggage Carts
Simplicate and add lightness.
A better choice for travellers attempting to go light, in my view, is the lightweight, well designed, Travelite luggage cart (shown at right). Made of aluminum and plastic, and riding on 3-inch rubber-tired wheels, it will hold up to 66 pounds (30kg) of load, yet weighs only 2.5 pounds (1.1kg), and collapses down to a tidy 16.5 × 10.75 × 3.25" (41.9 × 27.3 × 8.3cm) package. The Travelite isn't going to outlast a Concorde II by any stretch of the imagination, but if you should use it to the point where it wears out, its much more modest cost means that you won't mind replacing it with a new one. Alas, there does not seem to be a current retail supplier of this excellent lightweight cart. A number of similar carts are available, but I hesitate to recommend any in particular: most carts of this general type are not particularly sturdy.
In the absence of the Travelite cart, you might consider the Compact Folding Cart from Samsonite Luggage. It is not a model I have personally tried, but it garners the best reviews of any of these lightweight carts currently available. Made of stainless steel and ABS plastic, it weighs 2.75 pounds (1.2kg), and collapses to 15.5 × 10.5 × 3.5" (39.4 × 26.7 × 8.9cm).
Don't waste money on the cheap carts typically sold in airport shops, and designed with their manufacturers' interests in mind, not yours. They rarely work very well, or last very long.
Be aware that many airlines will not let you store a cart in the overhead bins; it must be placed under the seat in front of you. When possible, of course, leave it at home.
Finally, note that airlines rarely weigh luggage carts, or count them as extra pieces.
Dealing with Laptops
Where does the laptop go? Much business travel involves the transportation of a laptop computer. In North America, some airlines will let you bring one of these aboard in addition to your "official" carry-on, but I prefer to avoid the second bag when possible, and in my experience, it's almost always possible (assuming that you have the freedom to choose a reasonably slim, lightweight laptop — or tablet if these meet your computational needs — and don't get carried away with accessories). I carry mine in the padded center section of my Air Boss (or other three-compartment) bag; to stave off damage from below, I pack something appropriate on the unpadded bottom of such bags (such as the ever-functional sarong). The design of the Air Boss is such that a laptop is easily extracted from the side, for X-ray inspection at airport security checkpoints. And the fact that it can be reached via the short as well as the long side of the bag makes it a lot easier to extract from the overhead bin of an aircraft without removing the bag entirely.
Eliminating the separate laptop bag offers the additional benefit of making it less obvious that you're carrying an expensive theft-worthy device. It also makes the laptop somewhat more difficult for thieves to grab-and-run. Still, keep an eye on it when going through the security checkpoint, a common laptop theft location (don't let the laptop go on ahead of you through the X-ray machine; hold on to it until your own passage through the metal detector is clear).
If you crave further protection, you can place the laptop in a neoprene protective sleeve (as pictured at left, and widely available in a variety of sizes). If it's a simple sleeve, with no metal or other "suspicious" components adjacent to the laptop, you may be able to leave it in place when transiting airport security (though nothing is guaranteed when it comes to the demands of security personnel). Of course you'll still need to extract the computer from the bag. Some sleeves have attachment rings, which you can connect to your regular shoulder strap should you need a hands-free carry.
And yes, there's still plenty of room in the bag for the other items on my list.
Considering the Briefcase
Ah, the traditional briefcase: how does it fit the "travel lightly" philosophy? To begin, a classical brief case (i.e., a case for legal briefs, as seen in the photo at right) is almost exactly the same size as the "Air Boss" bag described above, so unlikely to be part of any single-bag travel plans. But once past that fairly obvious point, and into thinner attaché-style cases, we venture into the realm of "it depends". There's no consistent technique that applies to all briefcase-carriers, aside from common sense. If you truly need to transport enough business materials to fill a separate piece of luggage, then there's little that can be done.
If, on the other hand, there's enough room in your primary bag to carry what you need — and I've never had any trouble managing a reasonable amount of paperwork plus a laptop and accessories (though I more typically carry a small tablet) — then the problem becomes less one of utility than of appearances: the desire to look more professional when working with clients and employees. In my experience, most business travellers can utilize one of two approaches …
The sort of person I think of as a technologist — one who carries an abundance of technology and/or other work-related paraphernalia — can often get by admirably using the primary bag as a briefcase. As already noted, an "Air Boss" (for example) is no larger than a legal brief case, and, unless purchased in overly bright colours, looks quite tidy and businesslike. The person who is seeking a more high-level executive appearance should not be hauling around lots of stuff in any case: that sort of thing is for minions. A crisp executive image is better maintained with something like a thin, elegant, high-quality leather portfolio (as pictured at left), which will be easily accommodated by your single carry-on bag when not being used to impress plebians.
Finally, if you are more concerned about avoiding checked baggage than travelling lightly, note that — in North America — many airlines treat a (modestly-sized) briefcase or laptop bag as a "personal item", and allow it to be brought into the cabin in addition to your permitted carry-on bag. In most of the world, though, it's "one bag" only.