There’s a 2 hours direct flight from Bangalore to Agra (IndiGo 6E 5916).
IndiGo 6E 7928 flies from Lucknow to Agra.
From Delhi a better option is the Shatabdi Express (Train No:12002 & 12001 for return ) that takes just under 2 hours to travel between Delhi and Agra.
Another option from Delhi is the Taj Express (Tran no : 12280 & 12279 for return)
The cost of ticket is roughly Rs450 ( about USD 10 ) for this train one way , while an one way air ticket from Delhi to Agra is around Rs3500 ( about 80 USD). See also the Delhi to Agra train options.
During seasons there are special chartered flights that brings tourists in the Delhi – Agra – Jaipur route.

