The 2021 NFL season kicks off in Tampa Bay on Thursday, September 9th, with a full crowd scheduled to be in attendance.NFL commissioner Roger Goddell told reporters back in late March that he expects teams' stadiums to be full in 2021."All of us in the NFL want to see every one of our fans back. Football is simply not the same without fans, and we expect to have full stadiums in the upcoming season." Goddell said.All go for crowds at NFL games this seasonThe NFL recently announced that 30 of the 32 teams have been given approval to open to 100% capacity this fall.Already, 30 of 32 clubs have approval to safely open at 100% capacity before the 2021 preseason begins, league exec Peter O’Reilly said. The #Colts and #Broncos are the two remaining, but “both have a clear path” to get approval before August, O’Reilly said.— Tom Pelissero (@TomPelissero) May 25, 2021The two franchises who haven’t yet gained approval, the Denver Broncos and Indianapolis Colts, are expected to receive the go-ahead soon, as per the NFL Network's Tom Pelissero.Many NFL teams are welcoming fans back to training camp this year as things slowly return to normal in the United States.A crowd sized boost to the NFL’s bottom lineLast season's attendance dipped by more than 90%, with a total of 1.2 million fans included in attendance counts for the entire NFL regular season and postseason. Unsurprisingly, the NFL's revenues dropped substantially.The lack of crowds due to the COVID-19 pandemic also led to a reduction in the salary cap, retired players pension and injury payments.With fans returning earlier than many NFL officials believe, thanks to effective vaccination rollouts across the US, the drastic cutbacks the pandemic forced may be coming to an end.The announcement of a higher cap ceiling for 2022 indicates that the NFL expects money from new media deals and the return of fans to games to bring the salary cap back in line with the pre-COVID-19 projections.NFLPA leadership sent this email to players today, explaining the $208.2 million salary cap ceiling for 2022. Translation: The goal is get players out of “debt” ASAP after they received full salaries amidst a multibillion-dollar revenue shortfall in 2020, then let the cap soar. pic.twitter.com/e2iob9oigW— Tom Pelissero (@TomPelissero) May 26, 2021An electric atmosphere to return to NFL gamesAs hard as television networks and crowd special effects experts tried, there is no replacing the sound, feel and sheer electricity of tens of thousands of fans at an NFL game.The lack of crowds did affect just the players in the eerily empty stadiums but also the viewers watching at home, as piped-in crowd noise sounds had a hollow ring about it.NFL crowd recordsThe largest crowd ever to attend an NFL game was in 2009 at the Dallas Cowboys' AT&T Stadium when 105,121 fans watched the Cowboys take on the New York Giants.The loudest crowd was during the Kansas City vs New England Patriots game on September 29, 2014. The Chiefs fans reached 142.2 decibels at the Arrowhead Stadium.