No problem then:
https://www.thaiembassy.com/thailand/changes-visa-exempt.php
"Holders of normal passports of the following countries are granted visa-free travel to Thailand for a period of up to 30 days. The exemption is granted at most twice in a calendar year when entering over land or via a sea border but there is no limitation when entering by air."
I can attest to this, as I have been to LOS sometimes 6 times a year, all on visa waivers and always via an airport.
I've never had a problem, but I am always careful of overstaying beyond the 30 days, which are counted from the day you arrive.
Also be aware that if you fly into LOS, but then travel somewhere outside of the LOS and re-enter via a land border, then the counter is reduced to just 15 days from the re-entry date.
This bit me once after a side trip to Cambodia.
Cheers
SAG