Nobody had a problem with flip phones that play snake or Blackberry physical keyboards until the iPhone was demonstrated, and then nobody could conceive of ever going back (except in niche cases, e.g. journalists loved those keyboards)
Only if the airplane uses much slower ground based Gogo (?). I use it every now and then when taking the 45 minute flight from ATL to my parents home in South GA
The airlines have no problem with this. T-mobile has no problem with it either.