Granted that you truly can fly a set pattern (meaning a circuit around
your field, taking off going away from and landing coming
toward yourself) land with complete confidence and know how
to effectively trim the model, there should
be no reason not to treat yourself to a nice .40 class nitro or electric
4-channel trainer. All of them are pretty good but, I would honestly
stick with the park flyers for a little while longer and move up to an Aerobid Extreme
or something in that category (bigger and a little faster).

Sig LT-40
Carl Golberg Eagle 2- What I used after flying Firebirds and Aerobirds for a couple of years.
Alpha Trainer .40
Kyosho Calmato Trainer
Hobbico Superstar or Nexstar...

All good first nitro/aileron step-up planes.

These planes have a flat-bottomed airfoil with plenty of wing
dihedral. If you get into a bind, these planes can be flown much like
your Skyfly, with 3 channels- rudder, elevator and throttle. You won't be able to
land effectively with rudder only but, ailerons will be almost second nature
to you if you've mastered a 3-channel. Just make sure your winds are a little
low and ask an instructor or experienced flyer to trim it out and to show
you how and why he or she did it.

Welcome to the sport and have fun!

P.S. Don't forget to fly at least "three mistakes high" at first until you get the hang
of your model.