Keyword number 2 . southwest
Keyword number 3 . frontier flights
Keyword number 4 . flights
Keyword number 5 . frontier airlines flights
Keyword number 6 . spirit
Keyword number 7 . spirit airlines
Keyword number 8 . united
Keyword number 9 . united airlines
Keyword number 10 . american
Keyword number 11 . american airlines
Keyword number 12 . cheap airlines
Keyword number 13 . delta airlines
Keyword number 14 . delta
Keyword number 15 . cheap flights
Keyword number 16 . frontier air
Keyword number 17 . allegiant airlines
Keyword number 18 . allegiant
Keyword number 19 . frontier airlines denver
Keyword number 20 . southwest flights
Keyword number 21 . southwest airlines flights
Keyword number 22 . expedia
Keyword number 23 . frontier airline
Keyword number 24 . kayak
Keyword number 25 . frontier airlines baggage
