But the agency's 624-page drone rulebook, published Tuesday, also left the door open for a separate, more lenient set of rules that would apply to the smallest drones out there.

Based on the feedback it received, the FAA now says it will be releasing a new framework for what it calls "micro" UAS, or Unmanned Aircraft Systems, which would cover extra-small drones that are under 4 or 5 pounds in weight—and thus significantly less dangerous than their larger brethren.

In the public discussion draft of its drone rules (called a Notice of Proposed Rule Making, or NPRM) the FAA had proposed a less strict set of rules for drones in the "micro" category. But drone companies and interest groups that commented on the agency's plans argued that the rules were still far too restrictive for such tiny and relatively harmless aircraft.