Dress code This requires neat casual (business) attire and excludes track/sweat suits, tank tops, flip-flops, shorts and torn and/or extravagant clothing. Neat and tidy jeans are accepted. ISA travelers are not allowed to travel in airline uniform on KLM.

For standard commercial passengers, KLM Royal Dutch Airlines does not have a formal written dress code, provided your attire is not offensive, overly revealing, or a safety hazard. You will see people in everything from business suits to tracksuits. However, in 2026, there is a growing "civility push" in European aviation, and KLM staff may refuse boarding to passengers wearing clothing with profane language or aggressive political slogans. The rules are entirely different for "Non-Rev" (Staff) travelers or those using "ZED" tickets; they are strictly required to follow a "Neat Casual" or "Business Casual" code. This means no flip-flops, no ripped jeans, no gym wear, and no shorts. For the average traveler, the "unspoken" rule for a 10-hour flight to Amsterdam is to dress in breathable layers. Interestingly, a 2026 social media trend has sparked debate over "pajamas at the airport," but KLM remains pragmatic: as long as you are decent and respectful, comfort is king. The only exception is if you are lucky enough to be upgraded to World Business Class, where most passengers opt for "smart casual" to match the premium environment and the iconic Delft Blue houses.