بسم الله الرحمن الرحيم
When a person leaves his village or its outskirt then he becomes Shariah musafir. If the airport of Lucknow is adjacent to city then it shall be counted as outskirt and it would be necessary to offer full salah there and if it is not adjacent to the city rather separate then you would offer qasr salah on the airport.
Note: We have come to know that Lucknow airport is adjacent to the city. (d)
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.