This paper on application of Operations Research in Aviation industry discusses some of the well-known problems and their respective solution approaches, review current research in the field and highlight emerging areas of future importance. The paper applies concepts of Operations Research inclusive of Hungarian Assignment model and Critical Path Method on some of the airline companies. It deals with the shortcomings in the schedule of airlines, tries to increase productivity among crewmembers through crew assignment model and reduce time taken for non-critical activities, leading to an increase in profit for the airlines.