Imagine jetting off to a paradise like this and knowing you snagged a bargain fare. key to Mastering Travel on a budget. Studies show domestic airfares are often cheapest if booked 2–3 months ahead, and international flights about 90 days in advance. Booking early (and being flexible) can cut hundreds off your ticket. Travel + Leisure notes that adjusting your trip by even a few days can save big – for example, delaying a summer trip from early July to late August can yield nearly 30% savings.