Are there nonstop flights from Rayong (UTP) to Udon Thani (UTH)?

Yes. Thai Lion Air fly this route. Flight time is about 1h 9m.

Rayong → Udon Thani

U-Tapao–Rayong–Pattaya International Airport (UTP) to Udon Thani International Airport (UTH)・557 km

Nonstop flights available (1 airline). Flight time about 1h 9m. Nonstop return flights also operate.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.