NEW DELHI, April 2 (Xinhua) -- India's federal civil aviation ministry Tuesday said it was monitoring the situation of flight cancellations from Vistara airline.

A pilot crisis has hit the airline, forcing it to delay and cancel the scheduled flights.

On Tuesday morning, the airline called off at least 38 flights scheduled to take off from key cities due to a shortage of pilots. The number of affected flights is likely to go up until the evening.

On Monday, the airline cancelled up to 50 flights. And over 100 Vistara flights have been cancelled or delayed over the past week.

Vistara on Monday said in a statement that they have faced a "significant number" of flight cancellations and delays "due to various reasons including crew unavailability."

Reports said the pilots are calling in sick to protest the revised salary structure ahead of the Vistara's merger with Air India.