For Lukla and all mountainous airport around Nepal Himalayas, only smaller aircraft operates. The models are Twin Otter which is 18 seated aircraft, but due to load and heavy baggage, allows 15 to 16 passengers. The other similar type is  Dornier which is faster than Twin Otter with same seating order like in Twin Otter.Sometimes, the airlines also operates Pilatus Porter, a small aircraft of maximum 6 seated with single pilot. All these STOL aircraft are meant for Short Landing and Take Off. The Helicopter that operates on mountainous region are is Euro copter AS 350 Squirrel. Including Ecureuil helicopters are certified to fly above 2,300 feet / 7,010 m high. AS Euro copter AS 350 and Ecureuil models are most efficient and reliable for mountainous region like in Nepal Himalayas. The helicopter normally accommodates a maximum number of 5 adult passengers only. Subjective to high altitude and temperature on the landing site.