There is conflicting information now about iPhone vs. Android numbers (or course).
As I've said before, even if Android outnumbers iPhone, an Android programmer must deal with the fragmentation of the Android market. Some phone manufacturers are unable (technically) or unwilling (support, customization issues) to do upgrades of the OS on their phones. So you need to write for the lowest common version, abandon some segment of the market, or maintain multiple versions (which confuses users). How hard that would be to deal with for E-Ticket I don't know - depends if it uses advanced features.
And on top of that, you have to deal with the variances of the phones themselves (multiple screen sizes, etc.)