spamming never worked well for me, but old habits are hard to give up.It depends on how much time and real money you are willing to spend on this game. For a relaxed paced game I suggest not to rush to the big airplanes, and try to get the 3 stars or even compete the weekly rankings on turboprops and jets. Also begin the space program as soon as possible, it worth it. Some guys here have all these great buildings that drop valuable items for the space preparation and also produce a lot of money. Back in the first days here, I was wondering how @Captain WH Rollins was making so much money everyday only by visits, ... well as @Agent_L said, neighbors with planetariums, Astronauts Academy and Training Centers. Mission Control Center lvl 3 and red pad do the job, but their is no comparison to the other 3, especially Planetariums.
So, scan the signatures of the people here, some guys write these buildings and ask them for neighbors, your space program will take off.
I don't know if this gift spamming works good for you, but I believe that you can put this gifts in a better use here in the forum and also you will have the ability to control what you receive.
Happy Landings !!!!