Good way to tell when Aiden can open a door

Every vehicle you drive gets unlocked in the Car on Demand app for purchase after you have driven it once. So if you have already used the bike, it should be available for purchase there for 5000$. If you have not used it yet, here is where you can find it:

I have found a video, that shows a location where the bike spawns. Apparently, sometimes a dirtbike spawns instead of the chopper, so you might have to reload a few times until the chopper appears.

I have marked the location shown in the video on a map that I found on wiiware.in:

You can also unlock the chopper by playing a fixer contract, that requires you to race with it through the city, but I could not find out which of the fixer contracts is the right one. I will add the location if I find it out (or if someone else knows, feel free to share).

After asking Ubisoft about their policy on Watch_Dogs cheats with the game blocked from the Internet, this is the answer:

Bedankt voor het in contact treden met Ubisoft Klantenservice met betrekking tot Watch Dogs.

Mijn excuses voor dit late antwoord, wij ervaren op dit moment extreme drukte.

Het spijt mij te horen dat u problemen ervaart met de moeilijkheid in Watch Dogs en dat dit uw speelervaring vermindert.

Helaas moet ik u meedelen dat er een strikte 'No cheat'-policy geldt bij Ubisoft. Om geen mazen in het net te laten is beslist dit door te trekken over de gehele lijn op al onze spellen zowel online als offline. Ik moet u dus zeggen dat wij, conform onze condities, cheaten niet toelaten of officieel ondersteunen.

Mijn excuses voor het ongemak.

Indien u vragen heeft aarzel dan niet om met ons in contact te treden, zodat wij u verder kunnen helpen.

Translated: We have a strict no-cheat policy at Ubisoft. To not have any loopholes, the decision was made to apply this policy across the board, on all our games, both online and offline. So I have to tell you that we do not allow or officially support cheating.

I'm currently writing a followup to ask what steps I can take to help with my issue, without breaking their policy.

After asking for clarification, it appears the CS rep misunderstood my followup question. He clarified they only disallow 3rd party cheats. If you use a cheat the developer included themselves, it's fine. However, because such cheats are not officially supported, CS reps are not allowed to say if such cheats are in the game.