1

You should be fine. They probably won't even ask at immigration and if for some weird reason they do, just tell them your plan. Thousands of travelers take that exact route.

Enjoy your trip.

2

Your first problem may be leaving your airport. How long will you be in Thailand or away from home?

Where are you flying home from? Are you using 2 one-way flights? One one-way flight to Bangkok and another one home from Laos? Or are you returning to Thailand for your ride back home?

Round trip and one way flights almost cost about the same from the US to Asia on major airlines. Getting back to Thailand is cheap compared to flying one way from another nearby country.

Up to you.

3

If ya' don't have an exact plan as to when you will fly back to the US and when, here's what I did...I got the cheapest one-way ticket out of Thailand as a throw-away ticket to satisfy the airlines in the US....from Phuket to Penang was what I bought on AirAsia....in fact, they did not ask for an onward ticket, but they could...hope that helps...