Cheapest return flights from Ontario to Denver in April from $45

AirHint found the following cheapest return flights from Ontario (ONT) to Denver (DEN) in April 2026 (see full year).

Return flights

07 Apr - 14 Apr Frontier Airlines direct
07 Apr - 15 Apr Frontier Airlines direct
07 Apr - 21 Apr Frontier Airlines direct
18 Apr - 21 Apr Frontier Airlines direct
23 Apr - 25 Apr Frontier Airlines direct
30 Apr - 04 May Frontier Airlines direct
25 Apr - 28 Apr Frontier Airlines direct
23 Apr - 27 Apr Frontier Airlines direct
06 Apr - 10 Apr Frontier Airlines direct
10 Apr - 13 Apr Frontier Airlines direct
01 Apr - 09 Apr Frontier Airlines direct
30 Apr - 05 May Alaska Airlines

Also check the deals for one-way flights from Ontario to Denver in April.

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