'will have flown' is correct and can be used in written English.
You can use it to talk about something that will have happened by a certain point in the future. For example: "By the time the wedding is over, the balloons will have flown away."
At least someone will have flown a leftist flag in this sorry week.
If you don't have a toddler, Little Baby Bum will have flown well below your radar.
By that time all of the activities formerly han dled in San Francisco will have flown south.
By the time you read this, the space probe New Horizons will have flown right on by Pluto at some thirty-one thousand miles per hour.
While half the Dodgers squad plays here on St . Patricks Day, Torre and the other half will have flown to Beijing to play the Padres in exhibition games March 15 and 16, part of Major League Baseball's outreach to China.
It is that if the Paralympics achieve another of his ideals, by relentless examination of the precise help provided by prosthetics and a mass of categories which are inevitably arbitrary and in some instances just plain convenient, a perfectly balanced contest, they will have flown beyond all previous understanding of the realities of sport.
Yes, we will have flying cars Brad Feld | Feld Thoughts | 19 January 2014 A tech investor predicts: Electric-car sales will overtake gasoline-powered-car sales in the US by 2025.
(See: Detox. We'll have flying cars by the time that comes out).
"When we're through with them," he said, "they will have flies walking across their eyeballs".
"When we're through with them, they will have flies walking across their eyeballs," said Cofer Black, a leading CIA counterterrorism official.
When your pet is in need of something, there will be a "thought bubble" with their request and/or a "sign" that they need it (your pet will have flies and dirt around them if they are dirty or they will be sad if they want to play).
