Rail&Fly can be bought for any LH flight that departs or terminates in Germany, with the exception of some origins, viz.: to/from Amsterdam, Brussels, Paris, Salzburg, Vienna, and Zürich. Flights via Germany are not eligible for Rail&Fly (for instance, if there is a ticket for routing XXX-FRA-YYY-FRA-XXX and for some reason one flies XXX-FRA-YYY-FRA and would like to buy Rail&Fly justifying this by a long layover between YYY-FRA and FRA-XXX, Rail&Fly is not allowed, unfortunately. ...