One source said that Chicago police provided security for Meghan but did not give her an actual escort as she went through the airport.
In a candid interview with 60 Minutes ahead of the May 19 nuptials, the Australian writer said Ms Markle - who also describes herself as a feminist - had already sacrificed too much to marry the English prince, including her career and homeland.
Meghan Markle has made a brief return to the United States in order to apply for a UK visa. Before the wedding day, stayed a month, and still not aware of some interesting details, for example, who are the designers making a dress of the bride.
Meghan Markle smiles during a visit with Prince Harry to the Eikon Exhibition Centre in Lisburn, Northern Ireland.
They are scheduled to be Wednesday at Windsor Castle on May 19 and more than 2,500 people have been invited to attend the event. "With Prince Harry!'... She whispered it so quietly I had to ask her to repeat it", Nelthorpe-Cowne admitted to the Daily Mail.
The book also describes a cold side to the woman who returned her wedding rings to her first husband, Trevor Engelson, by post and would deliver a "Meghan chill" to friends "she no longer had the time for" as her star began to rise.
He said: "The emphasis will very clearly be on guests that Harry and Meghan know themselves".
The royal wedding is only five weeks away. Other preparations include a 6,000 space pre-booked auto parking area, food stalls and facilities, a team of 140 Royal Borough Ambassadors to help steward the event and decorations of bunting and ceremonial banners along the procession route.
Meghan's older half-siblings, Thomas Markle Jr and Samantha Markle, have reportedly not been invited.
A prominent Indian-origin chef and social entrepreneur said she squealed with joy when she opened a royal envelope that turned out to be her invitation to Prince Harry and Meghan Markle's wedding at Windsor Castle next month. "I can't think of single reason", she said.
USA host James Cordon also revealed this week that Victoria and David Beckham are going.