Further, if police wanted to track a suspect's moments across Schengen they could not. XYZ checks in for flight ABC, but in fact swaps boarding passes with an accomplice and travels to DEF and disappears. The police waiting at HIJ to intercept are left dumfounded.
But these checks don't exist if you travel by road, train, or even by foot. Therefore I fail to understand why you feel they should be needed specifically for air travel?