If the application is available at the site there are people who will apply, right? After a while they will have a look at the applications and if there are enough applications to fullfil the job openings they will close the application (in the most cases there are date openings -> closings). After the application is closed they will take contact with the appliers and make a date to test them. This takes (a lot of) time. The selections for the pilots isn't done in 2 days because they have to be judged and conclude the candidate is ok or not. This sub-processes take a lot of time and that is the reason why there are candidates which are hired a month of 2 - 4 after closing the application.