OK, I’m sure this has been addressed over the character’s long history. But wouldn’t about the worst part of his Clark Kent alter ego be plane flights? I mean, you’re sent by the Daily Planet to cover some Euro event in, oh, Brussels. How long of a flight is that, 14 hours or something? But since he’s on assignment for a newspaper, they’re buying his ticket, right? And if he didn’t show up for that flight, they’d hear about it, right?
So Superman’s basically as fast as the Flash, but no, he has to sit inside an airplane for 14 hours, and do a layover or two, so as not to blow his cover. Meanwhile, he could have flown over there and back on his own power like 500,000 times already. That’s gotta suck, right?
Or what if he’s sent overseas to cover a tsunami? You’re Superman, and you could fly over to Malaysia or whatever in like five seconds and be saving thousands and thousands of lives, but no, you have to sit in a business class seat for a solid day.