Light aircraft, minimum height?

[chilistrucker]

Daft question maybe, but thought i'd ask.
Is there a minimum height that these should fly at?
About 15 minutes ago it sounded like a small Cesna type plane was landing in my garden :0
The nearest airport is Southend, (10 miles away) and we're used to planes flying overhead here all the time as we are in Basildon so under a fair few routes. It was def a plane as we get helicopters land at the rear of our house all the time for Basildon hospital so i think i can clearly tell the difference between a helicopter and a smallish plane.

I can't believe how loud it was as it went over, and 5 minutes later a helicopter has turned up and been hovering since, followed by a fair few sirens.

[chilistrucker]

Thankyou both
Its gone quiet now, just struck me as odd though with how low the first noise was and i'm sure it was a plane.
Oh well.

[chilistrucker]

Mr Taxpayer said:

500' Minimum separation distance, that's vertical and lateral. It did allow me to fly a Gazelle helicopter along the line of the M6 through the Shap/Tabay pass.

I bet that was fun. Drove that route many a time in the wagon and really like it, i'm sure its much more fun in a Gazelle in fact from there all the way upto Glasgow you can often see some interesting low flying aircraft.
Thanks again all for the info, always like learning new things. It must have just been the helicopter and i heard it wrong, (could have sworn it was a plane though.)