Solved
Stutters/No input - Aircraft only
Game becomes unresponsive/stuttering @ ~1fps after a couple minutes of flying aircraft. Then after 30s to 2 min, recovers. Still stutters while in death/spawn screen until it recovers. Graphics card...
In case someone else has similar issue, ended up wireless x-box controller I only use for flying was low on battery, and somehow would bring my system to a halt. Changed batteries, no problems now.
