Again: How do you know?
The burden of (dis)proof lies at you, because everyday navigation tools rely on RE. Nothing relies on FE.
Everyday navigation relies on distorted maps, not globes.
*facepalm*
Do you read what other people post? Do you read any of mine? Really?
Not only have I read your posts, I asked you a question about them. You haven't answered...
Do you read anything I post? I've pointed out above how nautical maps ARE completely accurate
Completely accurate, yet distorted? 
Ugh...
This is not rocket science man.
All maps are distorted to some degree. The more surface area you try to show on a 2D map, the larger the distortions.
The trick is to have a lot of maps with small surface areas so the distortions don't cause significant problems.
Now, if the Earth was flat, there would be 0 distortions regardless of the size of the area you're trying to look at.
But for travel to be accurate and occur, distances need to be accurate. Flying from New York to Oslo, Norway is about 3,777 miles. A single flat map showing this area(upper Atlantic, lower Arctic Circle) would not be accurate. But because we know this, we can compensate and use the mapping techniques discussed earlier.
If the Earth were flat, we wouldn't need to do this.
Why do you think you never see a "distance" marker on a flat map of the whole Earth?