To clarify 49% FDI was always allowed in Indian aviation, what was not allowed was the direct and/or indirect investment of a single $ by any international carrier. The new regulation permits that but not in the direct route so allowing some vetting.
Air India is not currently part of this exercise and has been left out. WW has commented that till AI is under the govt. FDI by his airline does not make sense as AI has the ability to under price the market.
KF could always have gotten FDI just not from another airline. Lack of any PE from outside or even inside wanting to invest shows that his options are still limited. By guess is that QR will invest with him and he will become a feeder to QR to take some business away from EK. Option also is for EY who might pick up Spice stake as a feeder. Don't think any European carrier would want to pick a stake as there is not added benefit to them and they are not really flush with cash.
Jet and Indigo promoters can probably now cash out on the brand equity they have created by selling the NRI stakes to foreign airlines and since this was FDI they wont have to pay tax!!!! Might see these guys walking away laughing all the way to the bank as they will earn more this way than running either airline.