This is a bad idea. Its like cheating people. Why should we pay more because the airport cant handle traffic? Airport taxes have been already increased to cover expenses for increasing the capacity of airports . I would suggest that they should not increase fare for peak hours. rather they should decrease fare for non-peak hours. People who can travel during non-peak hours will do so and enjoy low rates. Others would pay the same and travel during peak hours. This will also reduce congestion.
Charging more from peak time travellers is rubbish idea.
