Thank you, God: the days of the check-in queue are numbered. Instead of the traditional hour-long shuffle along a gloomy, snaking line in an ill-lit, noisy airport, we’ll all soon be completing the formalities and choosing our own seats from the comfort of our home computers.

Last week, British Airways expanded its online facility, so all classes of passenger can now check in remotely, up to 24 hours before departure. It’s simple: from the “Manage my booking” button at www.ba.com, follow the instructions and pick your seat. (One may have been preallocated, but you can change it.) For domestic flights, boarding cards can be printed at home on plain paper; international travellers can use a self-service kiosk at the airport. Dump any bags at the fast-drop facility, go through passport control and you’re off.

The whole streamlined process means you don’t have to be at the airport until an hour before departure (two for US flights). Unfortunately, the service isn’t available for children under 16, so families are unable to skip the queues.

British Airways isn’t the only one at it. Virgin Atlantic is rolling out the facility, with online check-in currently available for flights to the USA, South Africa and the Far East, and BMI is considering its own scheme.

It should all make air travel a lot less hassle. But it does present us with a dilemma. Before, our position on the plane was at the discretion of the check-in staff. The sensible traveller was always very nice to them indeed: they usually have expert knowledge of the aircraft in their fleet, and winning them over could mean the difference between a quiet spot with an inch or two of extra legroom and 10 hours rammed between three crying babies and the toilet.

Now it’s all down to us — which is much more democratic, but a bit bewildering. The BA system presents you with a diagram showing the available seating in your class: so where should you aim to be? Even on the same aircraft, each airline will use a variety of different configurations, which makes finding the best seat a tricky business. The airline’s own diagrams can verge on the approximate, so they don’t give much away. Before you go to the airline’s site, visit www.seatguru.com, which lists many of the big carriers, including BA and Virgin Atlantic, with detailed diagrams of their cabin configurations and tips on the best seats to choose.

It’s not comprehensive, though: luckily, there are some universal rules to watch out for.

LEGROOM

In the quest for extra legroom, the first seat many economy passengers will want to bag is in the row by the emergency exit. Sorry, guys: they are specifically excluded from online check-in. Iata regulations say that passengers here need to be physically capable of helping others in an emergency — and to judge that, the staff need to be able to see you in person.

Next stop would be the bulkhead seats — those directly behind the partitions that divide classes, section off toilets and so on. They’re prized because they often (but not always) offer extra legroom. And wouldn’t you know it — BA excludes those too. But before you discard your laptop in disgust, consider the reason. This is where the bassinets for babies go on long-haul flights. If you don’t want to be serenaded all night by a disgruntled six-month-old, these seats are often best avoided: in fact, you might want to steer clear of the two or three rows behind them as well.

Study the diagrams carefully, though, and you can unearth some real finds. In a BA 747 jumbo jet, for example, a canny choice for economy passengers is often the window seat immediately behind one of the emergency-exit rows — usually seats A and K in row 29. To accommodate a cabinet for the inflatable emergency chute, there’s frequently no seat in front. As well as allowing you an easy route out without climbing over your neighbours, this lets you twiddle your toes in a gloriously empty space and bask in the hatred of the pained passengers all around.

If you don’t mind being at the back, seats B and J in row 52 are good bets, too: the tapering of the plane towards the tail means there is no seat next to you and plenty of legroom to one side.

TURBULENCE

Just like a ship, an aircraft moves around its centre of gravity. If you’re sensitive to motion sickness, or turbulence worries you, you want to be as close to that centre of gravity as possible. On most modern airliners, it’s just behind the leading edge of the wing: sit there and you’ll ride out the lumps and bumps in relative comfort, while those at the back of the plane receive the maximum buffeting.

NOISE

Again, the message is: avoid the back of the plane. As a rule, on modern jets, the closer you are to the tail, the louder the roar from the engines. (It’s the opposite for propeller planes, which is why, before jets became standard for long flights, first class was always at the back.)

RECLINE

Steer clear of seats directly in front of bulkheads or right at the back of the plane. All too often, they have little or no recline. A pain in the neck, as anyone who’s tried sleeping bolt upright for a 14-hour stretch will confirm.

SPEED

If you’re just taking hand baggage, or you’ve a connecting flight to catch, it’s handy to be near the exits used for disembarkation. On large aircraft, the forward door will always be used: if they do open up a second exit, it’ll normally be in front of the wing.

SAFETY

Whatever your friends may have told you in the pub, experts agree that, statistically, no one area of an aircraft is safer than any other. Sit near an exit if you like — but there is no guarantee that it’ll be used in an emergency.