I had the car you get from the mafia on the first island disappear. It was packed with stuff. The disappearing vehicles have not change since bp. I have had helis disappear in bp too, so I would assume they disappear in wg too.
Recommended is the white yot which you;ll have as a present from the lady guerrilla boss in NE part of Espada after completing her missions (as long it stays intact but same you can purchase on an Island far in the East), I used that one for traveling and it is less vulnerable like a heli and more reliable like a car which is anyway for one Island only ans subjects to disappear, I run thru the Indian ruins as well the CIA vessel and found the yot after where I did park it prior this long quest.