How many planes are in the air per day? Many thousands. Look up the websites for several of the major airlines, and count the largest flight number you can find, and that's the number of planes for just one airline. Only Alaska Airlines (not a big airline) reports an average of 20 flights per day. You also have to consider that there are Passenger airlines, Summer-only charter airlines, Cargo airlines, and more.I don't know how often military aircraft go flying. Some of that may be secret.