A foldable boarding ramp is operatively connected to a door opening provided in a body and is selectively extendable to the ground. The foldable boarding ramp is stored in a folded state inside a fairing covering a connecting portion between the body and a main wing. Thus, a reduction in the space of a passenger compartment and a cargo compartment due to the storage of the folded boarding ramp is prevented. In addition, an increase in air resistance can be suppressed without providing a dedicated fairing for covering the boarding ramp. Further, an interlocking member connects together a door for opening and closing the door opening and the boarding ramp when the door is opened. The boarding ramp may be automatically deployed to improve convenience.