Air Transport system has always been involved in all aspects of life because of its high potential in Transporting passengers and goods. In this research we surveys the effects of travel variables on demand of domestic air Transport, and for gathering required information from passengers, a questionnaire was designed including 20 effective parameters on air Transport demand with questions These parameters were investigated based on their importance using “ Factor Analysis” and finally proved that the factors “ price paid by passengers” , ” services offered by air Transport system” and “ time” has had the greatest impact on air Transport demand with more than 20 % influence. “ Structural equation Modeling” has been used for checking the “ Factor Analysis” results. The results of the model proved the correctness of factor analysis. Furthermore, the result of factor analysis has showed that the most important parameter has been “ low cost travel” with the factor load of 0. 9-1 in all case studies. Results show that both groups with factor load of more than 0. 5 in the obtained factors have identified the factor “ services” as the important and effective factor with the influence value of more than 20%.