This bike is packed with three compression members in place. 

When a bike is properly packed, the compression members will stand taller than bike parts in the case.
A packed bike should look like this (everything in the bottom half of the case) before you try to close the lid.

Compression members:

Compression members are used to keep pressure against the outside face of the case from reaching the packed bicycle. 

How they work:

Pressure is kept away from the packed bicycle by transferring loads from one side of the case to the other side through a 1/2" PVC plastic pipe which is held in place by two plastic disks. The disks can move sideways in the case to avoid added pressure against the bike if it shifts. To use this device, the first plastic disk is either placed in the bottom of the case before packing or once it's packed, the disc is slipped between the paced items to the bottom. After the bike is completely packed, a plastic pipe is inserted into the socket of the disk lying on the bottom of the case. The final step is to slip the second disk onto the top end of the pipe. 
Some people place the front wheel in the lid of the case then they try to close the lid while installing the top discs. It doesn't work. It is nearly impossible to lower the lid and wheel over the compression members. 
Compression members are recommended for use with the hard case or cardboard box only, not the backpack or lightweight cases. Using a compression member with a flexible fabric case might result in the compression member turning sideways which could damage the bike.  Approximate retail price is $9.98 per compression member.  Approximate weight, 130g

Keeping Compression members in place if the case is opened by TSA inspectors

When TSA inspectors open your case, the front wheel will stay in the lid and the top of the compression members will come off. The inspectors will close the lid when they are done looking inside and the compression members will not be functional because they won't go back on the tubes. To prevent this from happening, we have a TSA Security Net that solves the problem.