What are some security features on a plane?

Would they tell the general public if there were? I can’t see any benefit to anyone for airplane security protocols to be publicized.

T S A in USA !

I can confirm there are no keys/passwords in commercial planes. I’ve had to move them before (as an employee of the airline), which involves touching some of the buttons in the cockpit.

The security comes from the SIDA (Security Identification Display Area). At the airport I worked at there’s a perimeter fence and a control tower overlooking it. Everyone there either needs a badge or to be scored by someone with a badge.You’d have to break into the secure area and then jump into a plane. You could pull it off if it was parked in a spot where it could turn out of it’s own power, but not if it’s parked where it would require a pushback.

^Yes. The security measures are typically the responsibility of the place the aircraft are being kept.

From airstrips, to airports, security differs. But. Is essential. Mainly because aircraft, are a potential risk to national security or other air traffic, if not being flown by a pilot that understands the aircraft, and closely follows the advice of the air traffic controllers.

Some years back, a kid/teenager, made worldwide headlines, by stealing private small planes, from wealthy neighborhoods that were largely desolate because they are not primary dwellings. I believe he would break into colder harbor waterfront homes, have fun, then steal their plane.
He stole more than a few planes. If memory serves, he would usually crash them into water, or soft fields. “Barefoot Bandit” is suddenly ringing a bell.
But. It seems Ike, if you can start it up, taking of and flying, isn’t that hard.

It’s worth noting that in marinas, and other places boats/yachts/ships are kept, they are similarly really just protected by the hopes of keeping the wrong people out. The biggest difference being, a boat, can sometimes require more than one or two people to sail.
IF you snuck onto a dark and uninhabited bigger boat, you will have to be able to start its generators, unhook from shore power, and then crank the main engine(s.) Speaking as a former deckhand, this is typically not so easy. Often, there are issues like having to add oil to one engine every day, or you have to know which switches need to be on/off and it’s very complicated and often requires daily maintenance. Taking a decent sized boat, wouldn’t be easy. And you’d possibly get easily caught, if found out. If you get a plane off the ground, you’re kind of gone.

If you wanted to steal an aircraft, or something capable of air travel, it might be easiest at a hot air balloon gathering.

I know that many jet-ski rental companies have habits of leaving them with keys in them, on the sand. One could probably take off, with one of those.
But. You’re more likely to get caught in the water.
UNLESS, you steal a kayak, or canoe.