The Helios is an uniquely compact tandem, able to fit into even small cars with only minimal dis-assembly, but with the installation of its dedicated ‘separable’ system, it will fit into our Traveller case for transporting by plane. We designed the separable system of the Helios to be as easy to use as possible; the coupling and compression tube system working to stabilise and align the frame on re-assembly, and, for the single case pack, the transmission and braking systems staying in place. Having had significant experience of using folding and separable systems, both single and tandem, I have found flying with the Helios and Traveller case an unusually relaxing experience!