Eagle could definitely expand a lot, but the problem is we dont have any a/c to do so right now. There will be NO new aircraft for for AE until the MD80 replacement plans are set in stone (half the replacements will be 737s half will be some sort of 100seat product), the APA contract is hammered out, and 787s are ordered. I am guessing this will all be around 2009. When this happens I am guessing some 70seaters will be ordered for Eagle. AE wont see anything larger than that in my opinion.
P.S. this is all speculation! I am not that smart