“I wish I could say there was some definite way,” Caldwell says. “But they have two different goals,” safety and comfort or convenience.
“And passengers should be aware of that when planning flights,” she says. “The TSA wants everyone safe. And the airlines do, too. But further, the airlines have other issues to consider, like liability, and a different kind of safety.”
Where the TSA is thinking bombs and terrorists and other lethal things, airlines are also thinking about preventable common injuries and inconvenience.
“I can tell you that airlines don’t want things in cabins that, A, aren’t safe, and B, can’t be secured, either in the overhead bins, under the seats, or in a seat belt,” Caldwell says.
Large musical instruments can, in theory, be strapped into a seat, but unlike human passengers, those instruments can’t hang on in the event of turbulence.
Robert Palmer, a spokesman for the Canadian airline WestJet, which serves much of North America and the Caribbean, agrees.
“There is no rule banning cellos or any other specific musical instrument. However, they must be able to be stowed in the overhead bins,” Palmer writes in an e-mail. “If they are too large or of an odd shape, they must go below the wing. You cannot buy a seat for a musical instrument, because the seat and its restraint system are designed and rated for a person.”
A significant source of can-and-can’t confusion comes in the types of planes people are flying.
Caldwell says passengers should remember that if they have a flight with connections, just because an item was permitted in the cabin on the first leg of that flight does not mean it will be allowed on the second leg if the second-leg is on a smaller plane or an older-model plane with less in-cabin storage space.
“Maybe it’s a regional carrier, a partner of the primary airline, with smaller planes,” Caldwell says. “So if there’s any way to come close to avoiding the confusion, I’d say it’s to contact the airline and not just ask if an item is permitted but also try to find out the type of plane you’ll be flying on.”
James H. Burnett III can be reached at email@example.com. Follow him on Twitter @JamesBurnett.