In the season finale…
Do you think that When Lex woke up and found Helen missing and he went looking through the plane and found no one piloting the plane that the plane crashed?
I think it was a dream.
How else will they explain the disappearance of Helen in a small plane? She can’t just “vanish”
Uh…parachute?
Surely you jest Munch! Why would Helen jump out of the plane? Why would she leave the plane and not tell her new husband.
Nope your idea doesn’t wash with me.
Try again
Because she’s scamming him? She’s plotting her death? She’s been kidnapped by the pilot?
There are a bazillion reasons for her to leave/be taken off the plane. There are plausible ways to do so. This is a show about an alien who is impervious to bullets and where green rocks can make people walk through walls. Try to be creative. 
her=his
There are a few theories in this thread.
Plus the wedding has been on-again, off-again for most of the season. It wouldn’t surprise me if she’d decided that it was way off again. She could even be in league with Lionel.
she realized she was late for Kristen Kreuk and my wedding.
Um, let’s all ignore how my ranting killed that other thread, shall we?
Anyway, SPOILERS follow. (And there’s already been some in this thread, so I’m not using the box. So nyah.)
Anyway, the implication of the season finale was that Helen drugged Lex and left, presumably having finally given in to Lionel. (We supposedly see her slip something into Lex’s drink, but I suspect this is a case of a FOAF having revisionist memory.) Of course whether this is what truly happened is open to speculation. They both could’ve been drugged, Helen could’ve been kidnapped, etc.
Not that it really matters. Once you realized Lex Luthor was head over heels in love with this girl, you realized that she’d either betray him or be murdered, right? 
Hey, something’s gotta make him bitter enough to start hating Clark.
Just out of curiosity, when do you think they’re going to give him flight?
<< Hey, something’s gotta make him bitter enough to start hating Clark. >>
Not necessarily. Luthor hates Superman, but I don’t think he has any particular feeling towards Clark Kent, one way or t’other.
I would guess that they’re not going to let him fly until the show ends. Once he starts flying, he’s basically Superman instead of just “Clark Kent, teenager with weird powers”. Giving him the flight power would move too far from the core concept of the show.
Somebody, somewhere, suggested that the best ending for the show, when it finally gets cancelled, would be to have Clark put on the costume and fly off to Metropolis to begin his new life.