In response, Jordan executed two prisoners -- Sajida al-Rishawi
, a would-be suicide bomber whose release ISIS had previously demanded as part of a prisoner exchange, and Ziad Karbouli, a former top aide to the deceased leader of al Qaeda in Iraq, Abu Musab al-Zarqawi.
The pilot's father is demanding his country do more.
"These were criminals and there is no comparison between them and Moath. His blood is more valued than Sajida al-Rishawi and Ziad Karbouli," said al-Kasasbeh's father, Safi. "I demand that revenge should be bigger than executing prisoners."
His son's horrific death was recorded and the video was posted online Tuesday.
CNN is not showing the images, which drew global condemnation and prompted protests and vows of retaliation in Jordan.
King Abdullah has promised a strong response, saying that ISIS isn't just fighting his nation, but warring against "noble Islam" itself.
The country now wants to step up airstrikes against the terrorist organization, according to a source with direct knowledge of the situation.
But the pilot's uncle, Yassin Al Rawashdeh, told CNN that he also wants to see ground troops involved in the U.S.-led coalition against ISIS in Iraq and Syria.
Said the pilot's father: "I demand that this criminal organization (ISIS) ... should be annihilated."
'An earthshaking retaliation'
Demonstrators took to the streets in Amman and the pilot's hometown immediately after the video was made public.
One protester held a poster that read: "They burned our hearts, so let's burn their dens, and their prisoners in our prisons."
Jordanian government spokesman Mohammad al-Momani has vowed "an earthshaking retaliation" and "a revenge that equals the tragedy that has befallen the Jordanians."
Exactly what that response will look like remains to be seen, although the outlines of it are starting to take shape.
Jordan's military is seeking to conduct more of the anti-ISIS airstrikes assigned by the coalition, a U.S. official told CNN. According to that official, the number of strikes Jordan can carry out will depend on the location of the targets, weather and other factors.
Killing on big screens?
ISIS apparently made a big show of the pilot's brutal execution in Raqqa, its stronghold in Syria.
An activist network, "Raqqa Is Being Slaughtered Silently," reported that the killing was being shown, repeatedly, on large screens across the city.
One of ISIS' propaganda production outlets posted a video online that appears to show a crowd cheering as flames around the pilot grow.
The video features a tight shot of a boy, looking up as if in awe and saying that he would "burn the pilot" himself if he had a chance and that "all Arab tyrants should also be burned." The boy can also be heard saying "Obama the dog."
Because the video is carefully orchestrated propaganda, CNN has no way to know if people in Raqqa really feel this way, if other children were present or whether the video participants' responses were authentic or a result of intimidation.
There are anti-ISIS activists inside Raqqa who operate very quietly. One of them, with "Raqqa Is Being Slaughtered Silently," told CNN on Tuesday that on January 8, he was standing in the street when several ISIS fighters approached, bragging that they had set the pilot on fire.
Other ISIS members acted impressed but dubious, and a disturbingly juvenile moment ensued in which the ISIS fighters making the claim said that it was true, they were there and saw it.
Jordan last week said it was willing to release al-Rishawi, the would-be suicide bomber, in exchange for al-Kasasbeh, but the swap never happened. The Jordanian government repeatedly asked ISIS to show proof that the pilot was still alive.
Shortly after the video of al-Kasasbeh's killing became public, Jordanian military spokesman Mamdouh Al Amri said that authorities believe the pilot had been killed as far back as January 3, before ISIS began making its public demands for the release of al-Rishawi.
Pilot 'gave his life defending his faith'
King Abdullah arrived back in Jordan on Wednesday after cutting short a visit to the United States, where he met with President Barack Obama.
"The brave pilot gave his life defending his faith, country and nation and joined other Jordanian martyrs who gave their lives for Jordan," Abdullah said in a televised statement Tuesday, describing ISIS as a cowardly and deviant group that has nothing to do with Islam.
Al-Kasasbeh was captured by ISIS in December after his fighter jet crashed near Raqqa.
The pilot was one of eight children, according to the Jordan Times. He was from Karak governorate and graduated from King Hussein Air College, the newspaper said.
At the time of his capture, his father told the paper that his son was "a very modest and religious person" who memorized the Quran and "was never harmful to anyone."
U.S. Secretary of State John Kerry described al-Kasasbeh as everything ISIS is not: "He was brave, compassionate and principled."
"That he was murdered after his father's plea for compassion reminds all the world that this foe has no agenda other than to kill and destroy, and places no value on life, including that of fellow Muslims," Kerry said.
ISIS is known to be holding at least two Western hostages still: John Cantlie, a British journalist who has appeared in a number of ISIS-produced videos, and an American woman who is a 26-year-old aid worker.