My point was when confused between a best SAM system and a good Fighter plane, the choice should always be latter.
Fighter planes provide much better air defense than a SAM system.
India with limited budget and resources cant focus on both here one program always axes another, developing an all tier SAM system like S-400 will take equal amount of budget as MWF, we should continue the R&D on SAM also but focus should be Fighters.
Both fighter aircraft and SAM systems are effective in air defence role but SAM systems are better in comparison to fighter aircraft because of several reasons.
1. An aircraft cannot stay into the air forever, eventually it will begin to run out of fuel and will have to head back to its home base. A SAM system such as Patriot, THAAD or S-400 will not face such as issue as they are mounted on moveable truck chassis such as how Russia uses kamaz series trucks as chassis for their air defence systems such as Pantsirs, S-400, S-500, S-300.
2. The amount of weopons that can fielded by a single air defence is a lot more than what fighter can carry on their wing hardpoints, one S-400 SAM can carry have more than 100 missiles to launch at its disposal, tell me how many fighter can carry?
Take example of Rafale, F-22, F-35, F-15, Su-30, Su-35, all of them cannot carry more 20 AAMs at once, one SAM system can fullfill the role of more than a dozen fighter in terms of missile carrying capacity. With smart tactics and skilled operators, an integrated SAM will be much more useful as compared to any fighter aircraft.
Now what advantages do fighters have?
1. They are far more mobile as compared to an air defence system, the mobility of an air defence system is limited to the speed of its chassis vehicle which is not even 100km/hr. A fighter can fly more than six times that speed and hence can move from one point to another much more quickly and efficiently.
2. A fighter can be said to be much more Survivable against an AAM/SAM because they can employ tactics such as notching or employ S maneuver against incoming FOX-3 missiles such as R-77, AMRAAM, PL-12/SD-10 which helps to kinetically evade the missiles. In february 2019, two Su-30MKI aircraft of the IAF assigned callsign Avenger 1 and Avenger 2 respectively evaded multiple barrages of AMRAAMs fired by Pakistani F-16s. Any SAM system will face threats from air to surface missiles, especially ARMs such as HARMs. Both employ jamming but SAM systems if I am not wrong can generate a lot more power for their jammers, also any SAM battery such as S-400 will not be alone, they will be integrated with other missile systems such as pantsirs which can shoot down any incoming air to surface missile which is being targeted at the SAM battery.
At the end, it's upto us. The choice of choosing an aircraft or SAM depends on the scenario.