Here are the emails between Export-Import Bank officials and Boeing officials

When Congress required the Export-Import Bank to study how its aircraft subsidies to foreign airlines might hurt domestic airlines, Ex-Im chose an odd approach: instead of asking the airlines for help, the agency asked the subsidized aircraft maker to shape the study.

We know about this because of Freedom of Information Act request filed by attorneys for Delta airlines. I used FOIA to request the documents provided Delta–communications between Boeing and Ex-Im about the economic impact study.