Budget airlines GoAir and SpiceJet have also come out with discounted fares.
Air Costa's four-day discounted ticket offer began yesterday and is applicable on both economy as well as economy-plus classes, it said in a statement.
According to the airline, travel on tickets booked under the discount offer can be availed between February 8 and October 29, 2016.
The Rs 555 discount is applicable on final fare for all the bookings, it added.
The Vijayawada-based regional airline operates 32 flights per day from nine domestic airports, mostly in Southern India.
On Monday, no-frills carrier SpiceJet rolled out a special one-way low-fare offer, starting at Rs 826 sans taxes for domestic flights and Rs 3,026 plus taxes for an international journey for a limited period to commemorate the Republic Day.
The discount offer is applicable on select flights across SpiceJet's domestic and international routes.