I hope you're looking forward to exciting, in-depth discussions with US immigration officers in future
I had a look on ExpertFlyer and there's no trace of any IB flight MAD-TIP in the first half of 2009, presumably if such a flight was happening it would be in the system by now. I also had a quick search of the available fares LON-TIP and some cheap ones were coming up in March for KM (Air Malta), LX (Swiss) and 8U (Afriqiyah Airways, gulp). Not oneworld of course, but hopefully that gives you a starting point.