Here's the TL;DR on this:

Pakistani Inter-Services Intelligence (ISI) provides shelter and support for the terrorist organization Jaish-e-Mohammed, a Deobandi Muslim group dedicated to driving Hindus (ie India) out of Kashmir (and eventually out of India). Jaish-e-Mohammed is an ISI proxy but, much like Iran doesn't have total control over Hamas, Jaish-e-Mohammed doesn't do solely what the ISI requires. J-e-M is more of a decentralized organization like al Qaeda than a hierarchal one like Hamas or Hezbollah so there's a lot of individual initiative.

So when J-e-M drives an explosive-filled truck into a bus full of Indian SWAT, killing 40 of them, the ISI has plausible deniability (for broad definitions of "plausible"). If you're Pakistan, you obviously had nothing to do with it. If you're India, it's clearly a Pakistani attack, and an escalation of Kashmiri business-as-usual.

It's also rolling up on election season in India and Modi needs to look tough. Pakistan, for their part, lurrrrrv having Modi in office because he's the best bogeyman they've had in decades. So yesterday India rolled a shit ton of hardware - 12 Mirage 2000, 4 Su-30, 2 AWACS, a UAV and 2 tankers - and bombed... something. India says "terrorist camps killing 300-350 people" while Pakistan says "nothing" which, considering the five people killed in shelling immediately after were named and aged by Pakistan within hours, is probably the truth.

About twelve hours later Pakistan rolled three F-16s across the Line of Control and dropped bombs on Indian military installations. The Pakistanis claimed they never intended to hit anything and the Indians claimed they never hit anything - this is Pakistan saying "we could be dicks but we're not". India scrambled 56-year-old MiG-21s to chase them back... because that's what was on the tarmac. This is important to note: India has Su-30s, they have MiG-29s, they have Mirage 2000s. That they kept their front-line hardware on the Chinese border indicates the seriousness with which India is treating this adventure; the MiGs that ended up with the job were around when Kennedy was alive.

In any event, 56-year-old Indian MiGs managed to shoot down a Reagan-supplied F-16, although it made it back across the border before doing a lawn dart impression. The F-16s managed to shoot down an Indian MiG over Pakistani territory - its pilot bailed out. The Indians rolled an Mi-17 rescue helicopter to recover the pilot and Pakistan shot that down, too, killing both pilots. The Indian pilot is currently in Pakistani custody.

So. Two nuclear-armed countries bombing empty fields with the intent of hitting nothing and the guys that end up killed? Fuckin' search'n'rescue.