This relationship between the schools and the airlines has nothing to do with the airlines only believing that these schools produce good candidates, it is a marriage of convenience. The schools put the candidates through a selection process and then can focus the training on areas of interest that the airlines have asked them to do. At the end when the student is finished he/she will be put forward to interview with the airline, now up until this stage the airline has not had to put any input into the process except allowing its name to be used. The airline now has a pool of quailified, vetted students who are a known quality (not always the best quality, but a known one!!).
It is a win win situation for the school and the airlines, unfortuantly this is the was of the future.