You can readily identify an e-Passport, because it has a unique international symbol on the cover. Electronic System for Travel Authorization (ESTA) ESTA is an automated system that determines the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP). Authorization via ESTA does not determine whether a traveler is admissible to the United States.
Two to three weeks before the flight date, the price quotes start increasing. This is the time when business travelers start booking. While price drops are still possible, a chance of a price increase is much higher if you wait to book within this time period.
What's more, researchers found that average ticket prices were fairly flat during the window of time 50 to 100 days before departure. In other words, the best bet is to book 50 to 100 days beforehand: Tickets purchased during that period were $85 cheaper than the overall average for all domestic flight prices ($495.55).