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.
Alaska, JetBlue and Southwest don't charge anything to take advantage of a price drop, while other airlines charge $75 to $150 for domestic tickets, and more for international flights. So the price needs to drop more than that change fee in order for you to take advantage of the lower fare. None of the airlines actually gives you cash back; instead you get a credit good for travel on one of their flights in the next 12 months. Lockleer has been re-checking airfares for about five years, looking for price drops.