It is my opinion that there will be very little if any hiring at the majors for the next two years. After that, I think that many will start to slowly hire again.
I don't think that you are going to miss a "big wave" in the next four years. As long as you are able to get hired pretty quickly once your four years is up, I think that you will stay ahead of the majority of the hiring (leading to better career progression once you're at the airline).
But, its the airline industry so take my opinion FWIW.