collecting parking fee in theatre

If the collection of fee is legal or not solely depends on the fact that whether they have permission from any city authority or not. If they're doing so without authority, it would be considered illegal. 

Some time back, a petition was filed in the Gujarat high court against commercial complexes collecting parking fees in Gujarat. It was also brought to light how hefty parking fee at malls was leading to accidents as visitors instead parked their cars outside, also leading to traffic congestion.

Recently, the South Delhi Municipal Corporation (SDMC) threatened hospitals and malls charging parking fees with revocation of licenses. The body has issued public notices directing malls, office complexes, and hospitals, to not charge parking fees on numerous occasions over the last two years. Such establishments are now set to receive a final warning before the cancellation of licenses.

A while back, revenue officials in Kerala highlighted how shopping malls and hospitals in the city were charging for parking, in direct violation of the Kerala Municipal Building Rules (KMBR). According to the KMBR, permits could be allocated to a commercial establishment only if it had adequate parking space. Most visitors remained unaware of the fact that this parking fee collection is not legally permitted by the Corporation.

Back in 2014, the city Corporation had conducted a crackdown on illegal parking lots in the city’s cinema theatres, hospitals, and other commercial establishments. In Hyderabad too, commercial complexes in the city continue to charge for parking, despite government orders. While multiplexes are slowly falling in line, many complexes continue with the practice.

Coimbatore Consumer Cause has asked the civic body to not go ahead with its paid parking project in city, saying it would be contempt of court. 
In its order, the court had also said the Corporation was doing so without any provision in the city Municipal Corporation Act and rules and it could not collect such fee.

Get a RTI from the Municipal Corporation about the license or permission, then proceed accordingly.

If the parking lot belongs to the theatre, they can collect parking fees at their discretion

Inside they can, I paid so many times. Outside, they can’t.

Like do they sell and buy aircraft’s there or just run operations?