The maximum Delta SkyMiles available is 120,000 for either one or two round-trip coach tickets from the continental US (48 states) to Europe. There are no blackout dates. But, one will need to order tickets redeeming SkyMiles through the donor (not on one's own) to get the tickets--the sooner the better as SkyMiles redeemable seats are limited on each flight. SkyMiles can be used on Delta or any airline in SkyTeam, including Delta, Air France, Alitalia, Aeroflot, Czech Airlines, KLM, and Air Europa.