Can I keep a copy of company data on a USB drive?

No, this is not allowed without Executive VP approval and only for special cases. 

All data and work product created by you or anyone else at the company is the intellectual property of Christman and shall not be shared with external sources without proper executive approval.  Upon separation from the company you are not allowed to retain, copy, delete, or transfer any data or work product that is the intellectual property of the company without supervisor permission.  Doing so could result in the reversal of any separation package and the exclusion of any bonus that you may be considered for. 

Any data you receive and work with from a customer, joint venture partner, sub-contractor, or any 3rd party should be treated as confidential and only used for its intended purpose and not shared with anyone not associated with the project.