I wouldn't like to say. But I am just recently off the injury couch myself so I can really sympathise. I'm sure our brain plays tricks with us. Even though you have been swimming and cycling the brain has the power to tell us it is not enough. If you spoke to anyone who says they just swim and cycle they will tell you they get all the exercise they need. I was allowed to crosstrain but I missed being outdoors so much. That said it is best to recover as quickly as possible so you can get out there again and unfortunately that means listening to your body and putting no stress in your Injury. Whatever you decide make sure you are being honest with yourself.
I'm no expert but I would say probably no! Swimming and cycling I think are better for it at the moment. I have a friend with an Achilles problem and she has to be so careful. Have you seen the gp about it? They might be able to refer you for physio to help you get back?
Wouldn't you be putting stress on your Achilles tendon when cycling? It might be safer in your case to just stick to the swimming for a while, since that would have zero impact. Aerobics is going to have all the minuses that exist for running, and then some. (The aerobics I've seen involves a lot of jumping about, which is probably heavier impact than you'd get from running).
Tendons first, remember. In a year or so's time you can start to prioritise muscular fitness.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.