Loud planes not on flight tracker

[4x4Tyke]

Spread over the last 10-15 minutes, I just heard at least three separate flyovers in Hull, all sounded extremely noisy on full power, but above low cloud so no sighting. None are shown on flight tracker, does this mean they are military interceptions?

https://www.flightradar24.com/53.67,-0.28/10

[4x4Tyke]

Yep, found them on http://www.donnyradar.co.uk/live/flights?mil=1

With names like TRSPAS01/02, SCAR01/01 & WARLOR31 I'm guessing they are practicing intercepts.