Air Vice Marshal Greg Bagwell said the allies could now operate "with near impunity" over the skies of Libya.
He said they were now applying unrelenting pressure on the Libyan armed forces.
Latest reports say government tanks are shelling the hospital in the rebel-held western city of Misrata.
Witnesses had earlier said the tanks encircling the city had pulled back from their positions under air assault from international forces.
And there are also reports of fierce fighting between rebels and pro-Gaddafi forces in the strategic eastern town of Ajdabiya. Residents fleeing the town described shelling, gunfire and houses on fire.
Wednesday night also saw reports of a huge explosion at a military base in the Tajura region 32km (20 miles) east of the Libyan capital Tripoli.
US Secretary of State Hillary Clinton has again urged Col Gaddafi to step down and leave Libya.
UN Secretary General Ban Ki-moon has urged all sides in Libya to cease hostilities. "All those who violate international humanitarian and human rights law will be held fully accountable," his spokesman Martin Nesirky said.
AVM Bagwell was speaking during a visit to RAF aircrew based at Gioia del Colle in southern Italy.