I didn't care for this one, I'm afraid.
1. It seemed very after-school special-y, but with an unintentionally antisocial message. The main message I read from it is "You should always keep your promises, even to people that you hate. But when you do, don't be surprised if they f--- you over in the end." Um, okay, I guess. If that'd happened to me, I'd be inclined to never keep a promise again.
2. The aliens' behavior seems like nothing more than a plot element. Why do they make her wait til dawn? Why do they come ALL THE WAY HERE intending to pick someone up and then when it gets too crowded, don't take anyone.
Are they trying to accelerate human expansion into space? That was the impression I got while listening, but this is a pretty damned roundabout random way to do it that's liable to leave the only humans they meet more pissed than motivated, and anyone with sufficient knowledge and funding to support a space launch will ridicule these people rather than aid them.
Are they trying to teach her a moral lesson along the lines of the #1 above? Not sure why they'd want to do that.
Are they inscrutable aliens being inscrutable because it's their nature? I guess, maybe, but it didn't seem fitting in this case. I've believed it before in other stories, such as the Arilou in Star Control 2, but it didn't seem to fit here.
3. So a bunch of random people are going to launch a space program without funding or any particular expertise? No one mentions the great likelihood that they'll try for their whole lives and die on the planet just like everyone else, not to mention all the casualties from experiments with jet fuel, cryogenics, etc, that are likely to occur. In this way it reminds me of the Podcastle story where a small town scraped together money to launch a ship to Mars, despite completely misunderstanding the science behind it all (i.e. we need to develop plants that will grow in red light). In both this case and that one I felt like I was supposed to get a lasting message of hope from it. But refusing to actually consider the outcome of your actions is not hope, it's denial.