Qualifies as a carry-on with all airlines; fits underneath seat. Fastens directly to your rolling luggage; extremely light. Zippers extend the full height of the carrier, so pets can walk in comfortably. Chin rests on both sides of the carrier for pets to look out comfortably. The Incognito bag is rigid and flexible for folding, and there are peripheral layers for air circulation. Other features include: a safety hook inside, internal and external pockets.