How to properly support multiple languages? (And should my app do so?)

I've read a fair bit about localization on Android, but I've yet to find a single guide on how to implement localization at scale. The Android platform provides fairly extensive coverage for static apps - however, what if my app uses multiple online services that do not have multi-language support but do have (a very large set) of constant values that could reasonably be translated? Should this be done?

For example, I have an app that shows flight data and uses a service that only has support for two languages. If I wanted, I could add all flight statuses (Delayed/On-Time/Final/Boarding/etc), all cities and all countries to a few tables on an internal app database.

I have not calculated how much storage space this will take, but my guess is - this will require quite a bit of storage. Is the tradeoff worth it? I could also maybe launch my own service and query it, but I feel this may be a very expensive solution that only enterprises can afford.