to transport passengers between the airport terminal and aircraft, airlines use apron buses. An apron bus is often longer and wider than a normal passenger bus because it only provides services within the airport areas. As airlines seek to maximize the number of passenger per busload, larger buses are purchased and limited number of seats are installed so as to accommodate more passengers on single bus. This expedites the loading process. The apron bus door is also custom made to be wider for the convenience of the passengers as they usually have carry-on baggage