Phuket City airport offers the cheapest routes to Bangkok, from ฿634; whereas Bangkok Suvarnabhumi airport is typically cheaper if you're flying to Amsterdam, from ฿634. It's best to make sure you are flexible on dates to find the cheapest possible flight options for your journey.
Here are some of the cheapest flight destinations from Mount Kilimanjaro:
Fly from Bangkok to Phuket City from ฿634
Fly from Phuket City to Bangkok from ฿634
Fly from Bangkok to Chiang Mai from ฿667
Fly from Bangkok to Krabi from ฿967
Fly from Bangkok to Surat Thani from ฿1,067