Great question - DEL to DAY just means New Delhi Indira Gandhi Intl Airport to Dayton Airport. Now you’ll know what these unique codes when you look for flights! Mumbai Chhatrapati Shivaji Intl Airport (BOM), Bengaluru Intl Airport (BLR), Hyderabad Rajiv Gandhi Intl Airport (HYD), Chennai Airport (MAA), Ahmedabad Airport (AMD) are other airports near this flight route and their unique identifiers/IATA codes.