I'm not sure about your question but in Laos...
Lao airline have flights from ..
Vientiane (VTE) Laos to Sepon, Laos
VTE to Luang Prabang, Laos
VTE to Savannakhet, Laos (near future)
and I believe there's a few more.
But if you from the US and you're wondering if there is a flight from US...