It doesn't work for me. A friend wants to travel from Canada to Cayo Coco sometime in July. I can find flights with WestJet and with Air Canada - the latter, however, redirects to Air Canada Vacations where you can only search for a specific date and not for a whole month.
So I've tried various travel search engines. Check Felix now belongs to Kayak and has blocked Cuba. Opodo (both .co.uk and .de) send an error message when I search (and, besides, they would only allow +/1 day anyway.
Would anyone here have suggestions for a flexible search website?