Create a new strategy and set the primary movement strategy to "Ram". Then, go to Target Priorities and set the primary targeting priority to "Planets". Then, select only planets as possible targets in the list below. That might work.
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O'Neill: I have something I want to confess you. The name's not Kirk. It's Skywalker. Luke Skywalker. -Stargate SG1
Argh , didn't work. They immediatley went after the lone ship present, even though I set the only target as planets, and then retreated to the edge of the map, completely ignoring the planet!
Almost positive it's a bug.
Well that strategy is out the window. So much for researching fighters.