Courtesy Aircraft

Professional Aircraft Brokers



Courtesy Aircraft Sales

We assist aircraft sellers and buyers nationwide.

Professional Aircraft Brokers

Our Experienced Crew


Mark at the age of 14, bought a life changing 35 minute ride in a Mustang- an event that set his life’s ambitions in motion. He earned his private pilot’s license while still in High School and at the age of 18 he began flying T-6s and managed to sell his first of many warbirds.

Mark has been an aircraft broker for over 45 years and has sold in excess of 2,900 aircraft to date with Courtesy Aircraft Sales. And today, he has logged over 7,500 hours including more than 1,800 hours in high performance ex-military aircraft. In addition to his flying, he also holds an Airframe and Powerplant Certificate.

Having such a well rounded, as well as in-depth and hands-on knowledge of historic aircraft, it has made Mark Clark the “Go-To” person in this specialized aviation field.


Kathi joined Courtesy Aircraft Sales in 1997 and manages all accounting functions including accounts payable, accounts receivable, inventory, payroll, job costing and financial statements in addition to all Human Resource needs. She also maintains brokerage and purchase contracts, coordination of all closing paper work and any FAA related issues.

Kathi’s background is primarily in the accounting field but has also included sales and marketing support. She has worked in Life Insurance, high-end Home Construction, Industrial Construction, and Fine Dining Restaurant industries. She has built her career and experience mainly from working for small, local, family owned businesses.

Kathi was born and raised in a rural setting in neighboring Belvidere, IL. She currently lives in Rockford, has two grown daughters and two granddaughters and a grandson. Kathi is still fascinated by the warbird industry. “This is the greatest place to be — doing what I love in an environment everyday that most people can only dream about. To be able to see, hear, touch and even ride in these chariots of the sky is a humbling reminder of the history of an era gone by.”


Darcy joined Courtesy Aircraft Sales in July 2009 to provide sales, marketing, and customer service support. Her aircraft sales expertise range from General Aviation aircraft to Warbirds. In addition to aircraft sales, she is responsible for aircraft background research, maintaining photographs, writing and updating specifications on all aircraft Courtesy Aircraft has for sale. She is also responsible for the design of all sales and marketing material, as well as the company’s website and its maintenance. Darcy also coordinates public relations, newsletters, press releases, direct mail campaigns, and company sponsored events.

Darcy was first introduced to historic aircraft by her Grandfather, an accomplished Bristol Beaufighter pilot who served in World War II. He and her uncle, also a professional pilot, have inspired her to pursue a life long dream in the aviation field. Darcy started working in the aviation industry at the age of 16. The choice further strengthened her love of aviation which led to earning a Private Pilot’s license before graduating high school and a year later, an Instrument Rating. The path continued to Lewis University where she earned a Bachelor’s degree in Aviation Administration. Darcy has numerous years of experience in General Aviation airport operations, including airport line service, ground service, administrative support and customer service.

To-date, she has sold over 120 Civilian and Warbird aircraft with Courtesy Aircraft Sales. She’s looking forward to teaching her daughter about our great aviation history and how to fly one day!