Complex sentence: In the beginning, they were repaired and returned to their bases in France, but after Operation Torch (Allied invasion of Africa), the Spanish government interned the four aircraft that arrived (but crews were still allowed to return to Germany).
Split into simpler sentences: In the beginning, they were repaired and returned to their bases in France. After Operation Torch (the Allied invasion of Africa), the Spanish government interned four aircraft that arrived (although their crews were still allowed to return to Germany).