big airlines have enough delivers every day but small ones dont so they will use it to speed up delivers
An auction system inherently makes aircraft available only to the highest bidders. There is no way a small airline will be able to outbid a large airline with many billions in its war chest. Thus, the extra delivery slots will be won by large airlines.
Put another way, auctioning extra delivery slots as you proposed is the opposite of helping small airlines, because the large airlines they compete with will be able to buy even more planes while small airlines won't. If you then compare relative fleet sizes and growth, this would tilt the playing field even further in favor of large airlines.
Conceptually, it would be an interesting economics experiment to determine the true value of various aircraft in AE: start everyone with $5 million cash, make them bid for aircraft from the beginning, and see where the aircraft prices end up. Now I'm actually tempted to do this...