Book your ticket to Baltimore at least four to eight weeks before a scheduled flight departure. If you are planning a special Baltimore vacation, i.e. traveling around Thanksgiving, Good Friday, Christmas, etc., do not wait for a below-average kind of unexpected fare. Airlines know the demand and they keep their fares tight on the day.
Traveling on the festival day has its perk. The time of flight departure is critical too. For example, from New York to Baltimore on the day of Christmas, the flight with its departure by 4 in the evening or later, costs you less ($199) while when you keep the departure by 12 Noon or before, it costs you more or almost double ($402).