Pantnagar Airport is the nearest airport to Nainital. After that 70 kms distance has to be traveled by road through a bus or cab. People can also reach Delhi IGI Airport and travel another 300 kms by road.
You can reach Kathgodam Railway Station by train and it is 23 km away from Nainital. Any Major city of India has trains to Kathgodam railway station. A popular Train called Ranikhet Express runs from New Delhi & Kathgodam. After reaching there you can take a bus to reach Nainital.
If you are starting fromNew Delhi,the 300 kms road route has to be covered by a Bus. You can take a bus from Delhi kashmiri Gate ISBT and cover this journey in 7 hours approx.