UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.    )

Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐	Preliminary Proxy Statement
☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)]
☐	Definitive Proxy Statement
☒	Definitive Additional Materials
☐	Soliciting Material under Sec. 240.14a-12

________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________

Knight-Swift Transportation Holdings Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☒ No fee required.

☐  Fee paid previously with preliminary materials.

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14-a6(i)(1) and 0-11.

KNIGHT TRANSPORTATION SWIFT TRANSPORTATION KNIGHT-SWIFT TRANSPORTATION HOLDINGS INC. ATTN: PROXY DEPT. 2002 WEST WAHALLA LANE PHOENIX, AZ 85027 Your Vote Counts! KNIGHT-SWIFT TRANSPORTATION HOLDINGS INC. 2024 Annual Meeting Vote by May 13, 2024 11:59 PM ET V43097-P06148 You invested in KNIGHT-SWIFT TRANSPORTATION HOLDINGS INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on May 14, 2024. Get informed before you vote View the Combined Document online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 30, 2024. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Point your camera here and vote without entering a control number Vote in Person at the Meeting* May 14, 2024 8:30 A.M., Local Time Knight-Swift Transportation Holdings Inc. 2002 West Wahalla Lane Phoenix, Arizona 85027 *Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares.

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Voting Items Board Recommends Proposal No. 1: Elect twelve directors, each such director to serve until the 2025 Annual Meeting. Nominees: 1a. Amy Boerger 1b. Reid Dove 1c. Michael Garnreiter 1d. Louis Hobson 1e. Gary Knight 1f. Kevin Knight 1g. Adam Miller 1h. Kathryn Munro 1i. Jessica Powell 1j. Roberta Roberts Shank 1k. Robert Synowicki, Jr. 1l. David Vander Ploeg For For For For For For For For For For For For Proposal No. 2: Conduct an advisory, non-binding vote to approve named executive officer compensation. For Proposal No. 3: Ratify the appointment of Grant Thornton LLP as our independent registered public accounting firm for fiscal year 2024. For Proposal No. 4: Vote on a stockholder proposal regarding managing climate risk through science-based targets and transition planning. Against Proposal No. 5: Transact any other business that may properly come before the meeting. Other Action: In their discretion, the proxies are also authorized to vote upon such other matters as may properly come before the annual meeting or any adjournments thereof. Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Delivery Settings”. V43098-P06148