No landings or take-offs were allowed after a drone was spotted over the southern part of the airport area in the early morning, but the all clear was given shortly after 8.15am at Germany's busiest airport.
The aviation authority said 143 take-offs and landings were cancelled and 48 aircraft already in the air were diverted to other airports among a total of 1,500 scheduled flights on Thursday.
Several passengers had to wait in planes while the sighting was investigated.
The drone, which was approximately 1.5 metres in diameter, was spotted by several pilots.
Police are investigating and a helicopter tried to track the remote-controlled device after the latest drone incident to disrupt flights at the airport.
Police were at the scene investigating the incident. They tweeted to say flight operations had resumed at 8.18am.
Drohnensichtung am @Airport_FRA . Flugbetrieb im Zeitraum von 07:27 bis 08:15 Uhr eingestellt. Aufklärungs- und Fahndungsmaßnahmen der Sicherheitsbehörden wurden umgesetzt. Flugbetrieb seit 08:18 Uhr wieder aufgenommen. Unsere Pressemitteilung folgt. #BPol #WirSindSicherheit pic.twitter.com/ejXhY4Iva7
— Bundespolizei Flughafen Frankfurt am Main (@bpol_air_fra) May 9, 2019
In March, flights were grounded for half an hour at the airport following a drone sighting, also over the southern part of the site. It caused lengthy delays and the cancellation of 60 of the day's 1,439 scheduled flights.
In Germany, drone flights over the take-off and landing area at airports are strictly prohibited.
However, the number of drones being sighted is increasing. Last year, for example, German Air Traffic Control (DFL) registered 125 disruptions in the area around airports. The most disruptions (31) occurred at Frankfurt Airport, followed by Berlin-Tegel (17), Munich (14) and Hamburg (12).
In 2017, a total of 88 cases were reported in German airports, while in 2016 there were 64 incidents.
Is flying a drone legal?
Flying a drone is legal in Germany but strict rules must be followed. Drone flights over runways at airports are prohibited.
Drones are also not allowed to be flown over crowds, hospitals, prisons, government buildings, federal highways and railways. Drone operators must also keep their device within sight during the flight and not fly higher than 100 metres. There are exceptions at model airfields.
Control zones around German airports where drones cannot be flown can be viewed on the maps here.
The devices pose a major security risk. If they collide with an aircraft, they can damage its hull or engine. The main problem for air traffic control is that threats are not visible on the radar, DFS spokeswoman Ute Otterbein previously told the Hessenschau.
The figures are therefore based on information from pilots who report a drone sighting to the air traffic controllers.
Germany is not the only country to suffer from airborne pests. London's Gatwick airport was shut down for three days last December over drone sightings, causing holiday travel misery for tens of thousands.
As a result, the British government in March brought into force a no-fly zone for drones within five kilometres of British airports.