NEW DELHI, June 15 -- Noida International Airport began commercial operations today, with an ambition that looks straightforward on paper: scale up to 4.5-5 million passengers in its first year. In practice, it is opening into a far less forgiving backdrop-one in which India's aviation sector is slowing, airlines are cutting capacity, and demand growth may lag the pace of new infrastructure.

The airport will start operations with IndiGo and Akasa Air and plans to run about 12 flights a day initially before expanding services in July, according to chief executive Nitu Samra. The longer-term target is to connect to 18-20 destinations as capacity builds.

"We are in discussion with other airlines. So we expect that slowly," she said, adding...