Upgrade will not be 3-4 years at Eagle without significant growth aircraft. We have zero new airplanes on order, and I expect any we do order will first be used as replacements for the 135/140s. Fact is, Eagle is a mature Major airline without the benefit of significant attrition due to age 60 retirements. Only hiring at the other majors will drive upgrades, and that will take a long time. The top 800-1000 pilots will probably be very hesitant to give up over 10 years seniority to start at the bottom of a list now that pay/bennies/workrules at the legacy carriers have been decimated.
I was hired 2 years ago this month and honestly expect at least 5 more years to upgrade (and that assumes all flowbacks are gone in 3). I sure hope I'm way wrong.