On Aliexpress i see the excellent tablet holder.
I did not want to wait for 1 month, so I planned the same thing.
I designed to be printable without support.
It is easy to assemble, and can be folded in small sizes for carrying.
There are only 3 screws and 1 pc nut.
My other designed holder: https://www.thingiverse.com/thing:3383135
3mm X 30mm (max) for arm shaft
3mm X 20mm for ball joint base
The tablet clamp is for Huawei T3 7. Or you plan on it yourself, or I'll do it by sending out exact dimensions. (when my time allows)
Have a nice flight.
Update 2019. 06. 21.
Added sunshade for Huawei mediapad T3 7"
The axis material: 1,5mm2 copper electrical wire (whithout plastic insulation skin)
The holder plate printing suggestion:
lower layers (where curves) 0.1mm
upper layers (fillet) 0,2mm
Arm and joint parts í print 0,1mm, so that the curved surfaces are fine and accurate
Joint nut are fragile, it's better to print from PETG because it's flexible (I was gray at home)