Thai Airways International plans to use higher capacity aircraft on its Bangkok-Beijing route during the games because of a lack of landing and take-off slots at the Beijing International Airport.
THAI operates 14 flights a week on the Bangkok-Beijing route, using a mix of Boeing B747-400 jumbo jet and Airbus A300-600s.
It would use B777-300s or A330-300s, which carry some 300 passengers to substitute a A300-600 with about 260 seats, said Pichai Chunganuwad, vice-president for sales and distribution at THAI.
Bookings on THAI's Bangkok-Beijing flights during the Olympics, due to begin on Aug 8 in the Chinese capital, have been over 80% full.
However, difficulties obtaining Chinese visas during the sports event have constrained traffic growth. At best, the airline would see the same levels as 2007.
Olympic-related traffic so far has not improved the airline's overall China-bound business volume, which has been affected by reduced Bangkok-Chengdu flights following the earthquake that devastated the central province last May. THAI has reduced frequencies on the Bangkok-Chengdu route to three flights a week from five. The airline operates A300-600 jetliners that can carry 279 passengers on the route.
At best, the net result is THAI's business volume for the Chinese market this year would stay at last year's level, Mr Pichai said.
THAI serves six cities in mainland China from Bangkok, with a total of 55 flights a week.