A chap on an exchange tour on Tornados with the Luftwaffe a few years ago told me that "It was rather like the RAF once was". He'd flown his Tornado over to Brize along the airways for the sole purpose of doing his civil RT exam with me at the flying club, whilst his back seater had a coffee and chatted with some of our pilots. The cost? A few bottles of Wobbly - and of course he passed the silly exam with flying colours.
A couple of his German squadron chums had asked their boss if they could go to somewhere in Norway one weekend. "Of course, no problem - but why Norway, it's hardly the French Riviera?", he replied. "Well boss, we've found this great seafood restaurant which does a good deal in exchange for the odd bottle...", they told him. "Ach so - mind if I come too?" came the response.
At pre-pongo Wattisham (before the customs rules changed), a Luftwaffe F-4E would often appear on Friday afternoons, complete with a bright orange centreline tank as well as the Fletchers. After the crew had dutifully each declared their bottle and 200 to the customs officer, they waited politely until he'd gone, having said that they were waiting for some of their chums from TTTE to give them a lift.
Now you don't really need a 3-bagger to get from Germany to Suffolk, for in fact the centreline tank wasn't a fuel tank at all. So once the revenue had left and the transport had turned up, the crew would open an access panel and all manner of contraband would emerge to be whisked off to Cottesmore before the jet was towed into the hangar for the weekend. Sadly, after the tug driver had managed to clout the tailplane on a hangar door on one occasion, once the jet had been repaired the Luftwaffe squadron boss had no real option but to stop the visits, in case someone asked just WTF had been going on.