Airport Math

American Airlines Carryon Baggage – FAA security measures limit customers on all AA flights to one carry-on bag plus one personal item. The one carry-on bag must fit in an overhead compartment or under the seat. It should not exceed 45 linear inches (length + width + height) or weigh more than 40 lbs/18 kgs.

British Airways Hand Baggage – These allowances apply for all passengers entering the UK only: one standard-sized bag – maximum size of the bag, 56x45x25cm (22x18x10in), plus one laptop or briefcase.


We fly from Albuquerque to London tomorrow on two airlines and two tickets. (Never do this!) We like to fly British Airways because upgrading to Club World (Business Class with flat beds) is inexpensive and easy. Purchase a Premium Economy ticket and upgrade with 25,000 miles. We earn miles with flights and their credit card. You can do the whole booking online and their website shows you all dates where upgrades are available.

This will be our fourth flight with BA. We can fly from Denver, Phoenix or Dallas. For Denver we drive (in a rental car). For Phoenix we drive or fly Southwest (not so convenient because you cannot check bags all the way through). For Dallas we fly American Airlines and can check our bags all the way through.

For this trip we are flying from Dallas because there were more upgrades available. So we fly on a separate ticket with American from Albuquerque to Dallas. This is problematic if the first flight is delayed and you miss the second flight – I don’t think they will easily rebook you because you have separate tickets. But who ever heard of flights being delayed in the winter? 🙂 We almost cancelled the AA flight and drove to Dallas, but in the end decided to fly.

Which brings us to baggage. This is a two month trip, staying in one place. We need “stuff”. I wrote down the size for carryon baggage (or “hand baggage” in British). 45″ linear inches (22x18x10in). Guess how many times I measured the bag before I realized that 22 + 18 + 10 = 50? Many times. American says 45 linear inches. BA says 22x18x10in.

I bought our carryon bags for the BA specs, figuring AA is the same. I remembered reading on the message board that someone had problems on Air France for a too large carryon when they thought it was the right size, so I bought the smaller suitcase that fell well within the BA rules. Good thing, because it only just makes the AA rules. If I stuff the case it is too big.

Last year, traveling through Gatwick with their “one bag rule” (one bag only, no personal item), they pulled me out of the security line and made me shove my carryon bag in that metal thing that shows the maximum size. I had to pull my coat out of it (you can carry a coat onboard) and it still only fit in with me pounding it (and wrenching my arm). So, even though BA gives you the larger size, the largest size is a 20″ carry-on.

Briggs & Riley Transcend 20″ Carry-On, Size including wheels: 21″ x 14″ x 8.5″, Linear inches: 42.5″. When I measure it, including wheels, I get: 21.5″ x 14″ x 10″ (if you do not stuff it). Half an inch longer than 45″ allowed by American.

So – Airport Math. One airline has one set of numbers, another has a different set, and the security has their own numbers. Wish me luck tomorrow!

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Pauline Kenny

Pauline Kenny and Steve Cohen are US expats living in Dorset. We moved to the UK in 2010. Read about our move. If you would like to talk about travel, please join us on the Slow Europe Travel Forums.