while 戦 does indeed mean "war/battle", 作戦 means "tactics/strategy" which can be used in a military context but doesn't have to be. Japanese has a lot of compound words, so looking at just a single character can be a bit misleading.
...maybe you mean "cruise"?
Now, in the case of "crusades", the word has very negative connotation in Arab/Muslims countries. So, when George Bush said the war on terror was a "crusade", the vast majority of political commentators in the Arab world took this literally as religious war between the Christian and Islamic civilizations.