I posted a question on the Aviation SE that I really wanted an answer to. Its been up for a few days, but there are no answers for it. The link to it is here if you want to take a look at it. How do I get an answer to it, besides waiting for long periods of time?
Your question was only asked yesterday and this site doesn't get that much volume. Sometimes it takes up to a week for a good answer to appear (in a few cases much more).
There is a good post on this already on the main Meta site: Getting attention for unanswered questions?
So you have two main options. You can edit the question, which puts it back at the top of the "active" list. This should be an edit that improves the question, either by adding more information or by changing it up (such as including suggestions by Pondlife).
Or you can offer a bounty on the question, as Federico mentioned. This allows you to offer some of your reputation as an incentive for a good answer. This becomes an option after 48 hours, and you're only half way there right now.
You asked it yesterday, that's definitely NOT a long time. This one for example is almost one year old. You cannot always expect to receive answers in a matter of minutes of StackExchange sites.
If a significant time passes and no satisfactory answers are given you can offer a bounty.