[Vanilla] Attacking into Fighters

[DCIII]

All - I am attempting to siege an enemy's capital. He has one ocean border but a fighter patrolling over that hex. I've been able to bombard his walls and city health down to zero, but I am unable to take the city by sea because I'm not allowed to pass through this fighter with my naval melee or embarked units. Do I have any options other than damaging it with other fighters or taking the city with a land unit?

Any insight on forcing fighters to vacate a patrol without other fighters would be helpful.

Thanks.