The national carrier has about 650 commanders out of about 1,300 pilots.
Flights to Mumbai and Delhi were delayed.
"A section of Air India is observing a go-slow since this morning, leading to delay in flights," sources told news agencies.
As per reports, the Labour Ministry excluded airline commanders from the workmen category, effectively meaning that commanders can no longer form a union.
Under the Industrial Disputes Act, 1947, a non-workman is defined as an employee who is mainly in managerial or administrative capacity, or who draws wages exceeding Rs 10,000 per month.