If you want to fly into Utapeo, you really need to research which international flights fly from the countries you intend visiting to Utapeo.
My feeling is that you will really strictly limit your options (and costs may be higher too) by doing this, there will many more flights into Bangkok, which is really only an extra 40mins travelling time from Pattaya
You should be aware that the Pattaya airport (UTP) is in U-Tapao in Rayong province about 1 hour drive away. Suvarnanabhumi airport (BKK) is about 1.5 drive from Pattaya and the bus connections are much more frequent and cheaper.
That's really what I wanted to know so thanks for your reply