The best you can hope for is perhaps to lay some thin plywood platforms down over the bottom truss members and use them to store lightweight items.
Best material to use for attic flooring.
Attic space offers many options for building storage or living space especially if you already have a well built basic flooring in place.
Weight concerns if you do have an existing walk up attic with traditional floor framing the principle concern when converting the space into a living area will be weight.
Use 1 foot wide boards in pine or spruce to make quick work of putting down a floor.
Be cautioned though that even with insulation hardwood flooring will cause a lot of foot traffic noise to the floor below.
Adding a floor to an attic can increase storage space or create a new room.
You can for instance use recycled materials.
Before you start creating a floor for your attic you must make sure that it can handle the additional load.
The decision regarding the thickness of plywood to use for the subfloor in the attic has a lot to do with how you intend to use the attic and it also depends on the spacing of the ceiling joists.
If your intent is to use the attic for a purpose other than storage you will need to consider a more finished look.