[rdl]

They're clearly objectively better in a lot of ways; you could just argue that they're not net-better overall, since there are also advantages to twins. Single is undeniably cheaper to buy/operate. Since you never push off without both engines good, there's no way a twin would have higher dispatch rate than a single (since there are ~twice as many parts to deadline your aircraft).

You may still value "has extra engine in case one dies in flight" more than this, though. (and I did, until I saw how singles actually had approximately the same safety stats as twins, at least for private pilots most like what I'd be.)

[Recoil42]

I wonder if twin-engined aircraft are less better maintained for the reasons you mentioned. Since you only have one engine to 'push off' with on a single, you better make damn sure it's in good working order.

[rdl]

That's ETOPS vs. 3/4 engine aircraft, I believe, but I don't think the maintenance and reliability standards are appreciably different for civilian 1 vs. 2. Mainly because no scheduled service is done using a single engine, so it doesn't even come up.

I'm pretty sure military maintenance standards are so entirely different that their extensive experience with single engine aircraft isn't meaningful -- plus, their singles are mainly either very military specific (F-16 and other light fighters) or historical. Most of their transport aircraft have something in common with commercial, now, except maybe C-130s. And the USN has generally favored twin vs. single for "reliability over water" anyway.