I agree with the others that the symptoms are consistent with insufficient tension on the non-driving side. The combination of only 32 spokes, the dish and exposure to vibration in the plane were sufficient to loosen the non-driving threads just a little. Your riding did the rest. All the non-driving side spokes were probably damaged. If you have a lot more to go on your trip, you may want to consider getting a new wheel (preferably with 36 or 40 spokes).

However, I gather that you are still persistent after 10 broken spokes and want to continue on this wheel. The extreme dish with today's 7, 8, 9 and 10 speed cassettes creates an extreme difference in the tension on the driving and non-driving side spokes. Spokes need a certain minimum tension to keep the nipples from unthreading and for the spokes not to knock at the elbow. Increasing all spoke tension to get this minimum tension on the non-driving side runs the risk of pulling the spoke through the rim, especially with only 32 spokes. Then you will have to replace the rim, as well.

Here's one trick you can use to increase the spoke tension on the non-driving side without changing the dish. Use a spoke pattern on the non-driving side that results in a significantly longer spoke for that side vs. the driving side. For example, if the driving side is X3 you may want to try a X4 on the non-driving side. This will make the tensions on the driving and non-driving sides much closer together, than if they used the same pattern.