Flight Tonight helps travelers search for the cheapest round-trip flights departing from the US or overseas within the next 2 to 24 hours.
Tnooz did a test search for flights out of Dallas. Flight Tonight kicked back a long list of truly 11th-hour fares, sorted by price.
A $301 trip to San Antonio was the best available deal on short notice. A same-day flight to Cancún was $538 — though it required a seven-night stay.