While I was at a festival just down the road from Conigsby last year, the BBMF Lanc flew over at what seemed like tree-top height.
Not much is more impressive than four Merlins at full chat about 100m above your head, lovely sight!
(We also got to see a Spit and a Hurricane, and the Vulcan XH588 flew over the day before, I'll be keeping my eyes peeled again this year. Actually, four Bristol Olympus's are pretty damn impressive as well)