Congratulations on improving your credit! It is a long road for sure.
You have two CC, and it will take some time to build up your file. If you know you are going to be paying for the tickets, have the cash available, an option to consider is the AMEX Serve, Prepaid card, or if it is available near you, the similar though slightly different American Express for Target, Blue prepaid card. Either will allow you to pre-fund the card, then use it like an AMEX to purchase the plane tickets. For incidentals and other costs, or costs outside the US and Caribbean, the CapOne cards should work. Neither of these AMEX cards are going to help build your credit, but they can help to make certain types of payments that are larger than your current CC can handle.
Good job with building your credit!
Even though you have some unsecured credit, if you have funds available you may want to consider a secured card for $2000 or $2500. This would accomplish a couple of things. First, it would give you the room for larger credit purchases such as the plane tickets you mentioned. Managing a higher credit line than what you have now will look good to future creditors. Second, with a larger CL showing on your file, you would likely get higher limits on new cards you app for in six months or so. When you get better established, you can close it and get your money back, likely in a year or so. Just a thought. Of course, it's all moot if you don't have the cash available.
Good luck to you.
