airstair

thumb|DC-3 modified with a simple airstair thumb|Northwest Airlines [[Boeing 727 with ventral airstair open]] thumb|right|3-section folding airstair on a "Combi aircraft|Combi" [[737-200 aircraft of Alaska Airlines]] thumb|George W. Bush boards a [[VC-25 using the lower-level airstair.]] thumb|The Il-86, a wide-body airliner with airstairs into the lower cargo level. The rear airstair is also visible in this picture. thumb|The airstair on a business jet thumb|There were no passengers to accommodate on this business jet conversion for cargo operations. A manually-placed, folding airstair saved weight for crew access to the cockpit. An airstair is a set of steps built into an aircraft so that passengers and crew can get on and off without needing help from outside. The stairs are built as part of a door or are lowered from inside after a door has been opened. Airstairs do away with needing a mobile stairway or jetway to get in and out of an aircraft. Some of the earliest aircraft with airstairs were the Martin 2-0-2 and Martin 4-0-4. Some Douglas DC-3 aircraft were retrofitted with airstairs. As the infrastructure of airports developed, the need for airstairs decreased.

The cabin doors on wide-body aircraft are significantly higher above the ground than on narrow-body aircraft. When airstairs have been a requirement, as on the VC-25 and the Ilyushin Il-86, the airstairs go into the lower level cargo hold, with steps inside to get to the cabin.