Whatever the benefits of online conferencing and cyber networking, when the meeting matters, people like to meet face to face. Modern air travel makes that practical on most occasions. However, if you don't get your cabin baggage sorted, you may find you're unwittingly extending, or even doubling, your journey time!

While it may only take an hour to fly from London City to, say, Amsterdam Schipol, if baggage has to be checked in to the hold that means arriving up to two hours before take off. At the other end, there can be a further wait of up to an hour to collect that baggage. A one hour flight can be extended to three or even four hours, wasting time and generating stress.

That's the main motivation behind carry on or cabin baggage: to take advantage of late check-in and to walk off the plane directly into a train, taxi or hire car. You can also take work on board to make use of the time spent on a long flight.

However, one man’s reasonable item of cabin baggage may well seem like a steamer trunk to the person next to them or to the Cabin Crew. In the past, this lead to not a few unfortunate incidents, as large and unwieldy items were coaxed and prised from the clenched fingers of passengers for whom even a brief wait at the baggage claim would wreck their schedule.

Oh boy, does size matter!
So, to avoid such unpleasantness, and the delays to which it can give rise, airlines specify what will be acceptable as cabin baggage on their flights. But even that could go wrong if a passenger were to change airlines, only to find that different dimensions applied on their next flight.

To clarify what can be carried on board an aircraft, the International Air Transport Association (IATA) has endeavoured to establish universal dimensions, shape and weight for cabin baggage. These specify that the overall dimensions (length plus width plus depth) of cabin baggage items should not exceed 115 centimetres (45 inches).

This is generally interpreted as a length of 56cm (22in), a width of 45cm (18in) and a depth of 25cm (10in) including wheels, handles and side pockets, i.e. that will fit under the seat in front or in the overhead locker. However, life is rarely that simple.

Most airlines interpret the IATA guidelines (although IATA and the airlines have pressed for them to be enshrined in an international standard, that has not yet happened) as a wheeled case that is 55cm by 40cm by 20cm. However, as the overall limit is 115cm, that might include a holdall or a suit carrier, as long as a suit carrier’s depth does not exceed 20cm.

And, in addition to those dimensions which are designed to ensure that cabin baggage can be stowed safely and not impede exits in the case of an emergency or fall from the overhead locker (an emergency in its own right), airlines impose a weight restriction according to the type of aircraft and the strength of overhead lockers. This is usually between 6-7 kilograms (13-15 pounds) per item but, again, may vary according to the airline’s operational priorities and local conditions at the time of boarding.

First among unequals
Of course, some passengers will be treated as more equal than others in this, as in any aspect of air travel. So, while the people at the back of a BA plane are allowed one 50x40x20 cm 6kg bag, the champagne-swilling passengers up front in First Class and Club can add a briefcase or laptop up to 45x35x20 cm with the whole ensemble weighing up to 18kg. BMI are a little more generous with European and UK passengers allowed up to 7kg within the dimensions of their one item and transatlantic passengers allowed 10kg in economy up to 23kg (max per piece 12kg) in the Business class.

Very little about air travel today has not been affected by increased security considerations and there is a long list of items that cannot be carried in cabin baggage, ranging from the obvious (toy or replica guns, knives and household cutlery) to billiard cues and tradesmen’s tools. Also, manufacturers of other types of equipment than luggage have realised that a product that can be carried onto a domestic flight as cabin baggage has more use than one that cannot. So a number of items from portable projectors to sample boxes, portable offices and even a fold down bicycle are now available in carry on proportions.

The best way to find out what will be acceptable is to check with the airline or go to their web site – they can all be accessed from the IATA site. As a last resort, passengers can ask check-in staff to pass their baggage items through a template to check width and depth and into a measuring bin to check length; these are usually located just before the X-ray machine.

But it’s always best to plan ahead where possible and especially where a tight schedule assumes that an item will not be stored in the hold. That way, you can avoid cabin baggage becoming a right carry on!