Does aerobics burn more calories than weight lifting?

When it comes to burning calories, your heart rate is much more important than what it is that you are doing. If you can reach and sustain the same heart rate for the same amount of time you will burn pretty much the same amount of calories regardless of activity.

Usually aerobics would keep your heart rate up more consistently than weight lifting, so for the same period of time, aerobics would burn more calories.