How long does each flying lesson last?

Whilst studying your Recreational Pilot Licence (RPL), you will generally spend around 2-2.5 hours at the airport — 1 hour in the air, with the remaining 1-1.5 hours split between classroom briefing, aircraft preparation and debriefing.
When you are studying your Private Pilot Licence, you may need 4-6 hours at the airport — which will be made up of 2-4 hours in the air, with the remaining 1-2 hours split between flight planning, classroom briefing, aircraft preparation and debriefing.