The most common method of entering Bhutan is via air into Bhutan’s only International Airport located in Paro. Once your travel dates have been confirmed, they will book your flight and arrange all formalities required of entering Bhutan. This includes the Visa clearance letter. On arrival at the international airport in Paro, this letter will need to be endorsed by the immigration officers before you are issued with a Visa permit.
The best way to enter Bhutan is by Druk Air, the national air carrier. As Druk Air flights may be delayed because of weather in the monsoon (July & August), it is advisable to keep a 24-hour gap before any onward international connections.
And also Bhutan Airlines being the country’s first private airline. It has always strived to provide excellent services to the people with the lowest fares possible.