The Lufthansa '
animals' web site indicates that the maximum dimensions of an in-cabin pet carrier are 55 cm x 40 cm x 20 cm, which is approximately 21 in x 15 in x 8 in.
This is similar to the acceptable dimensions of a hard-case carrier for U.S. carriers, 17.5" L x 12" W x 7.5" H, but quite a bit shorter than the acceptable dimensions for soft carriers, 18” L x 11” W x 11”H.
How strict is Lufthansa in enforcing the maximum dimensions? Could I bring a U.S.-sized soft-sided carrier on a Lufthansa?