“Within 24 hours of the American strikes, monitoring groups reported that jets were once again taking off from the bombed Shayrat air base.”
Of course they were. You might wonder why the jets weren’t all destroyed and why the base isn’t a smoking ruin after the missile attack. The answer is that the US notified the Russians of the attack to give them time to evacuate, and the Russians notified the Syrians (because of course they did) and it’s safe to assume that the Syrians removed everything important that they could before the attack. Airstrips themselves are relatively easy to repair.
I’m not sure if the attack represents a change in policy, or is more of a one-off impotent theatrical gesture. If the former, then eventually we’ll kill some Russians, and I don’t know where that goes. If the latter, then that’s par for the course for Trump, in my opinion. Anyway here is a nice short (7 minute) summary of the Syrian civil war, if you want to know what sort of mess it all is.