This would best be achived via the server_monitor.sqf.
if (_ownerID != "0") then {
means its a locked vehicle.
if (_object isKindOf "Air") then {
means its an air vehicle, like helis or airplanes.
then you would set
_object setFuel 1;
for it to be fully refueled at server startup.
_object setDamage 0;
_hitpoints = _object call vehicle_getHitpoints;
{
_hitpoint = _x;
_selection = getText(configFile >> "cfgVehicles" >> (typeof _object) >> "HitPoints" >> _hitpoint >> "name");
_object setHit[_selection,0];
_strH = ("hit_" + (_selection));
_object setVariable[_strH,0,true];
} forEach _hitpoints;
[_object,"repair"] call server_updateObject;
This makes it fully repaired on server startup.
