有区别。
attendant是常客，出席者，参加者的意思。
attendee强调是（会议等的）出席者。
例句辨析：
attendant
1、He was a regular attendant the opera.
他是剧院的常客。
2、The difference between being a church attender and a church member is commitment.
参加教会和成为会员的分别在于有没有委身。
3、The ultimate blunder for a red carpet attender could be showing up in the same outfit as another star who looks better in it.
红毯嘉宾的大忌可能要数与其他明星撞衫了，尤其当别人穿起来更好看时。
attendee
1、Only one-half of the attendees could fit into the large hall at any one time.
这个大厅一次只能容下一半的出席者。
2、This attendee has declined the meeting.
此参加者谢绝了会议。
3、This attendee has tentatively accepted the meeting.
此与会者已暂时接受了会议要求。
