For most of this month, the sole operator of the route is raising the frequency from five flights per week to seven flights, an airline executive said.
The extra flights started on May 5 and will end on May 30 when the airline is expected to revert to its previous frequency.
Much of the demand this month will be driven by officials attending the 24th Asean summit, scheduled for May 11-12 in the Myanmar capital Nay Pyi Taw.
Bangkok Airways continues to use a 70-seater ATR-72 turboprop on the route as it does not see sufficient traffic to deploy the 138-seat Airbus 319 or 320 single-aisle jets, even during a peak period.
Since late last year, the airline has enjoyed a monopoly on the route connecting Bangkok with Nay Pyi Taw, which is mostly served by Myanmar-registered carriers on domestic routes.
Low-cost carrier Thai AirAsia (TAA) pulled out of the route linking the Thai and Myanmar capitals barely one month after launch due to subdued travel demand.
TAA's daily service, operated by a 180-seat A320 jet, was dropped right after the 27th Southeast Asian Games, the region's largest sports event, which was hosted by Myanmar in December.
Bangkok Airways has been able to sustain its service on the route, which it started on Sept 30, because its deploys a turboprop with a capacity that matches actual traffic demand and has lower operating costs than its competitor's larger aircraft.