United has round-trip flights from Houston (IAH) to Guatemala City (GUA) for $137, NONSTOP. Flights in September. Departures on Tuesday, Wednesday, and Thursday. Origin/Destination reversible.
Note: United “Basic Economy” fares do not include a free carry-on bag. Only a personal item (like a small laptop bag) is free. Seats are randomly assigned for free prior to boarding.
Note: The personal item size on United flights is smaller (9-in/10-in/17-in) than Frontier or Spirit (8-in/14-in/18-in).