Yes, they do fly to those 3 locations, but that's not their main operations. These airports where one legacy airlines dominate and have all the gate space with no airspace issues make easy for the main airline to run on time.

For JetBlue, what matters is how well it does on flight into/out of BOS and JFK. That's where it's compete for the customers. It doesn't matter to a Boston resident how on time Delta is out of ATL or how AA is out of DFW or how JetBlue is on MCO-LAX, he/she cares about JetBlue's performance out of BOS, especially on routes he/she flies on.

If a legacy airlines flies 70% of its operation out of fortress hub and are on time 85 to 90% out of them and then also flies 15% of its operation out of JFK/BOS and are on time 70 to 75%. It's nationwide otp might be around 85% still. If 75% of JetBlue's operation touch BOS/JFK and are on time 70-75%, then it's otp is going to be 73%. But to people out of JFK/BOS, that kind of OTP is fine and comparable to competitors.