Q. Do any of the travel sites allow you to do flexible searches for international flights? Most that I have seen require exact dates for international flights. The only way to compare different dates is to do multiple searches. The flexible grids -used by Travelocity and others- showing +/- 1-3 days would also be nice.
A. Actually, Travelocity does offer international flex searches now, just not for all routes. Previously, you may recall, they allowed international flex searches but failed to tack on hefty fuel surcharges, and the Department of Transportation objected and asked them to cut it out altogether.
You might also want to try ITAsoftware.com. although you can't book through them, it's good for reference; and ZUJI.com is worth a look although it prices in foreign currencies and isn't always accurate.