United and Delta are generally regarded as having the most overlap w/ LCC's - not sure which is higher. Most of United's key routes out of Chicago (sometimes MDW
) and Denver have LCC's in them; OAK
is LCC heaven and right across from SFO
. Only IAD
doesn't have a huge LCC presence but that is quickly changing. Keep in mind LCC's have had a stable existence in the west (where UA
is strong) for 10 years or more; the LCC invasion on the east coast was settled in the west years ago.
Delta has LCC competition up and down the east coast (including ATL
) and now has it on the key ATL
-west routes. SLC
is very LCC driven and even DFW
is getting into the action although AA
overshadows Delta at DFW
has no LCC's but is a small local market and is surrounded by cities w/ an LCC presence.