With my mod hat dusted off and put on, it's been long established that the framework of our game rules and mechanisms are geared soley towards naval construction. Air and Ground forces, economic development, and even massive infrastructure projects like the Mexican Canal or northern sea routes have not been supported by game-mechanic resources, but soley as narrative development.
In short, the only restriction on development of non-naval anythings is what the board, in collegial fashion, agree is reasonable. Generally, so long your news and board interaction lay a plausible enough background, and concerns of the board are addressed, most anything goes. The only problems that crop up is when players have pursued projects against repeated and strenuous objections from the rest of the playerbase.
With the mod hat off, I of course continue to be frustrated by the constant determination that The World Will End In 1950. Even if the board in general decides to discontinue play (which there is no compulsion to do other than the need to account for technologies beyond Springsharp's current programming), that is an entirely OOC issue, and no nation should be played with an aim to "get things done" or "not waste their resources" by any specific date without sufficient in character justification. If there's projects that make sense for your nation to start, but won't finish by 1950....start them anyway.