Hi John,
iFly GPS does support the same type of Tower and Obstacle alerts. It may just be a setting that is keeping you from seeing them. Touch Setup, Alerts and Warning, and then make sure the Terrain Alerts are on, set to moderate in the beginning. Currently the Towers/Obstacles are combined, but I'd like to see the Terrain and Towers/Obstacle split apart into separate alerts. Many may no care about ground terrain, but very much care about the tall tower and obstacles. Stay tuned.
ps- I think you'll find iFly GPS works pretty nicely on the towers, we even highlight that specific tower on the screen with a magenta halo that coincides with the audible and textual alert. I hope this helps.
pps- I think we also have it on the list to increase the size of the towers, maybe even have a smaller / larger setting.