13D Filing: Senator Investment Group and Gogo Inc. (GOGO)

This Schedule 13D is filed by:

(i) Senator Investment Group LP (“Senator“), with
respect to the shares of Common Stock directly held by certain investment funds with respect to which it acts as investment manager
and has investment discretion (the “Funds“);

(ii) Mr. Alexander Klabin (“Mr. Klabin“), as Co-Chief
Executive Officer of Senator, with respect to the shares of Common Stock directly held by the Funds; and

(iii) Mr. Douglas Silverman (“Mr. Silverman“),
as Co-Chief Executive Officer of Senator, with respect to the shares of Common Stock directly held by the Funds.

The foregoing persons are hereinafter sometimes collectively referred
to as the “Reporting Persons.” The general partner of Senator is Senator Management LLC (the “Senator GP“).
Messrs. Silverman and Klabin indirectly control the Senator GP. Any disclosures herein with respect to persons other than the Reporting
Persons are made on information and belief after making inquiry to the appropriate party.

The filing of this statement
shall not be deemed an admission that any Reporting Person is the beneficial owner of the securities reported herein for purposes
of Section 13 of the Securities Act of 1934, as amended, or otherwise. Each of Mr. Klabin, Mr. Silverman and the Senator GP expressly
disclaims beneficial ownership of any of the securities held by the Funds.