Ooty is a popular summer spot of South India. From Lucknow there are flights to chennai and from chennai you need to travel to Coimbatore and then take a bus up the hill. If you are lucky you might get a direct flight to Coimbatore. You need three days minimum to spend in Ooty. There are packages which range from 10k to 12k. Kindly check with MMT and Yatra. They cover a lot in one package.