The chief executive of Qatar Airways has said the measures taken against Qatari air traffic should be declared illegal.
Akbar Al Baker made the comments to Al Jazeera on Monday, a week after Saudi Arabia, the United Arab Emirates, Bahrain and Egypt closed their airspace to Qatari flights as part of a series of measures against Doha amid a major diplomatic rift.
The four countries cut diplomatic and transport ties with Qatar on June 5, accusing Doha of backing "terrorism" - charges that Qatar denies.
"We expect our friends to stand up with us in this unfair, illegal blockade conducted by four countries," Al Baker said.
Al Baker also expressed his "disappointment" over recent comments by US President Donald Trump, who called on Qatar and other countries to increase their efforts against "terrorism".
In his remarks on Friday, Trump said "the nation of Qatar has historically been a funder of terrorism at a very high level", but he failed to provide any evidence.
Trump said that during his recent visit to Saudi Arabia, "nations came to me and spoke about confronting Qatar over its behaviour. So we had a decision to make: Do we take the easy road or do we take hard but necessary action?"
In response, Al Baker called Trump's comments about Qatar "ill-placed" and "ill-informed".
"I am very disappointed in the leadership of United States. We are an ally of the United States against terrorism; we are an ally of United States with bringing stability into the region."
Qatar is home to the vast Al-Udeid airbase, the biggest US base in the Middle East, which holds the forward headquarters of Central Command and hosts some 10,000 American troops.
"They have the biggest base; they have 15,000 Americans living here, and there are many more thousands of British and Europeans staying here," Al Baker said.
"I want the American people to realise that they are trying to intimidate a small country which has the closest relation with the United States."
In a separate interview with CNN, Baker also called on the International Civil Aviation Organization, a United Nations body, to declare Arab measures against Qatari air traffic illegal.
"We have legal channels to object to this," Al Baker said. "International Civil Aviation Organisation ... should heavily get involved, put their weight behind this to declare this an illegal act."
The UAE, Bahrain and Saudi Arabia have signed the Chicago convention, which is administered by the the International Civil Aviation Organization.
Any country party to the convention should grant freedoms including "the privilege to fly across its territory without landing".
Qatar Airways has been hit hard by the dispute, with 18 destinations now out of bounds for the airline.
In addition to closing their airspace to Qatar Airways, Saudi Arabia and the UAE have also shut down the airline's offices.
"It is actually a travesty of civilised behaviour to close airline offices. Airlines offices are not political arms," said Al Baker.
"We were sealed as if it was a criminal organisation. We were not allowed to give refunds to our passengers."
In a separate interview with The Wall Street Journal, Al Baker said he would not delay any plane orders or put expansion plans in other countries, such as India, on hold.
On Sunday, Qatar Airways reported a 21.7 percent rise in net profit in its last financial year that ended in March, fuelled by a strategy of investment and expansion
Source: Al Jazeera and news agencies