They had portable piers during the cold war where lots of ships in the middle of the ocean would link up and provide services to other ships... ie fuel tankers and supply ships would be part of the grouped ships so you could sail up in a destroyer and take fuel and stores on board from the ships attached to the group.
In this case I would think they are talking about light transports like An-12 or Il-276 at most, or Be-200 for fire fighting or arctic patrol.
Remember pontoons linked together can allow a tank to cross water, so bigger pontoons linked together could certainly allow aircraft to land on water.
It would not be mobile enough to replace a real carrier, but would make sense if you want a relatively fixed landing location off shore where there is no ground and putting it on ice is unpredictable because of varying ice thicknesses at different times of the year.
At the bare minimum you could land fighters or helicopters and have ships sitting along side these pontoons with fuel or armaments for refuelling and rearming...
It would be partially moveable, but not designed to actually move around.
It could be expanded and shrunk down as needed... a few container ships could probably lay down extra sections or pick them up as needed.