A growing number of travelers are opting to vacation in the fall instead of the summer in an effort to beat crowds and sky-high peak season prices.Aleh Varanishcha/Getty ImagesSome luxury travel agencies say more travelers are vacationing in the fall instead of summer.One company now sees more bookings for September than June, July, and August.Travelers can dodge Europe's peak summer crowds and costs by going during shoulder season.Planning where to go for your next summer Euro trip?No need to stop by Portugal to try some sardines.