I've kept S osphromenoides (chocolate gourami) over the years & more recently S vaillanti (samurai gourami) - the latter are by far the better jumpers, but both choco's are rather talented at finding the smallest gaps & leaping outward ...
Surface cover is helpful with these fish, but if startled (consider nighttime traffic re cars or people walking through the house) these fish can/will fly - you don't mention tank size ... some ambient light or moonlight (dim white light - what moon on what planet shines blue
) may reduce startle reflex jumping.
Also take note if fish are fighting, again this can trigger jumpers, especially if tank is small.
Lowering the water level can help I suppose .... I keep mine in rimmed tanks with water level lowered by a couple inches ... last week I had 3 vaillanti jump despite them having been in the tank for months without incident ... for lack of anything else to do, I've closed the window blinds - no jumpers since
BUT last week was also a week with more determined disagreements so I suspect this is more the trigger
A few weeks ago, I lost 2 chocolates to jumping - again the only real change I observed was increased wrangling within the group - & yet I've moved subordinate fish to other tanks only to have them act miserable & refuse to eat without their "family" - after a few days I give in & return them to the group & observe instant "happy" fish activity & color
I haven't noticed any "net" effects with choco's except be very careful when netting, as again they will go from apparently quiescent in the net to flying through space
If you do find a recently jumped fish, place in a large net & float in tank with gentle current across gills to assist fish with breathing - my last jumper was stunned & appeared almost normal after 15-20 min, I released him back into the tank after an hour or so