European nations have the right to impose penalties on airlines when their planes roar too loudly above built-up areas near airports, the top adviser to Europe's highest court said Thursday.

European Air Transport (EAT), a unit of the DHL group, has asked the European Court of Justice to strike down a fine imposed by Belgian authorities after one of its planes exceeded maximum evening noise levels over Brussels.

The company, which was fined 56,113 euros (some $76,000), argues that the Brussels regional legislation violates EU rules on operating restrictions because it measures noise levels on the ground, not from the aircraft.

But the court's advocate general, Pedro Cruz Villalon, said the Belgian law is not in violation of the EU directive because it does not prevent take offs and landings from Brussels airport, but merely provides for fines.

Villalon also pointed out that the European Court of Human Rights has found that noise pollution forms part of the environment and that "aircraft noise gives states grounds for taking active protective measures."

He said: "The protection of fundamental rights -- in particular the fundamental right to private and family life, and home, and the right to environmental protection -- justifies the adoption of such measures."

The advocate general's opinion is non-binding but the European Court of Justice agrees with it in 80 percent of cases.