A Frontier Airlines passenger was denied boarding at Harry Reid International Airport (LAS) on Friday after the carrier switched the aircraft operating his flight to Denver International Airport (DEN), according to a report by 9NEWS. Being denied boarding normally brings to mind airline overbooking, where a carrier sells more tickets than an aircraft has seats and must ask passengers to volunteer before involuntarily bumping travelers. The DOT itself recognizes passengers denied boarding because of smaller-aircraft substitutions as involuntary denied boardings for reporting purposes, even though they may not qualify for compensation. Luckily for the affected Frontier passenger, he ultimately received some compensation from Frontier after 9NEWS brought his case to light. Passengers who encounter a similar situation should document the aircraft change, keep their booking and boarding information, and ask the airline to explain the reason for the denied boarding.