As a rule, the best times to book a vacation are during periods of economic expansion. These include late summer and early fall as well as mid-January through late February. This is because high demand for airfare results in lower rates and more availability. However, this does not mean that low prices persist throughout the year or that booking last minute is always the best option. In some cases it can be worthwhile to wait until airline capacity increases before booking tickets at full price. Another good time to book vacations is during school breaks from May through July since flights tend to be cheaper those months due to less demand from parents traveling with their children on field trips or other excursions into nearby cities for educational purposes). Lastly, if you’re looking at taking a trip where you will need an international flight – such as going abroad for business – then waiting out holiday seasons may be worth your while since outside of US domestic travel schedules pollution levels often decrease substantially over winter holidays resulting in lower fares across many airlines leading up to Christmas & New Years so check online first before making your final decision!