./fgfs --enable-freeze
to start with simulator in pause.
i have to press 'P' twice to pause after startup.
Flightgear 3.7 / 1d34b9
Ubuntu 14.04.3 LTS
also, looks like a long standing issue: http://thread.gmane.org/gmane.games.flightgear.devel/39633/focus=39636
Laurent fixed this and provided a patch:
http://thread.gmane.org/gmane.games.flightgear.devel/79473
This is solved.
Fixed per [f110fc]
Last edit: Gijs 2015-12-14