A wheel fell off a Boeing 757 plane Monday just after a United Airlines flight took off from Los Angeles. It’s the second time that has happened to a United Airlines plane this year. The flight touched down safely at its destination in Denver.A wheel fell off a Boeing 757 plane Monday just after a United Airlines flight took off from Los Angeles. It’s the second time that has happened to a United Airlines plane this year. The flight touched down safely at its destination in Denver.