My experience in air-layering or marcotting a Rangoon Creeper has had very limited success. Out of the thirty or more marcots I air-layered from the rangoon creeper atop our garden gate arch, only two rooted. Out of these two, only one was really healthy and thrived.
If only the rangoon creeper vine had fruits, I would've planted all the seeds I could get and patiently wait for some young seedlings to sprout. But alas, our rangoon creeper vine wouldn't even bear fruit.
Because it's not easy to propagate, I realize now why this vine may be difficult to find. The well-established vines being sold are oftentimes expensive.