I saw these tankers coming out of Aviano and watched them via FR24 to somewhere north of Majorca. I think they then went on to somewhere near Rota and then I saw perhaps a couple of them later in the day over northern France northbound, presumably going back to Mildenhall (cant say for sure as I was otherwise occupied). I think some of the C17's have been tanking in the Western Med/Gib area and carrying on eastwards.