Yes, as a general rule, European airlines enforce smaller carry-on dimensions than major US carriers. While a typical "standard" US carry-on size is 22 x 14 x 9 inches (56 x 36 x 23 cm), many European "full-service" airlines like Lufthansa, Air France, and British Airways stick to a similar 56 x 45 x 25 cm limit. However, the real "shrinkage" comes with European low-cost carriers like Ryanair, EasyJet, and Wizz Air. Ryanair’s "priority" carry-on limit is a strict 55 x 40 x 20 cm, and their free "small bag" (personal item) must fit within 40 x 20 x 25 cm. Furthermore, European airlines are much more aggressive about weight limits. While US airlines rarely weigh carry-ons, European carriers often impose a limit of 7kg to 10kg (15-22 lbs). If your bag exceeds these metrics, you will likely be forced to pay a "gate-check fee" which can be as high as €60 ($65). If you are traveling between the US and Europe, it is wise to buy an "international-sized" 20-inch spinner rather than a domestic 22-inch model to ensure compliance.