Luke, you're welcome for the help there, but I have to question your height assessment....Fixed wing Mil aircraft (apart from light ones) are only allowed to transit below 250 feet in certain areas of the UK, and even then, not below 100 feet MSD (Minimum separation distance), unless departing / approaching an aerodrome. I'd accept that a C130 might look lower, but if he was below 250 feet in your part of the world, he was perhaps bending the rules a little!