Speaking on LBC, Mr Farage said: 'Let me ask you, does any of you seriously think that if an application to fly an Obama blimp, of Obama as a young, crying baby above Parliament Square when he came here during the referendum to tell us to vote remain, do you actually think that would have been allowed?
'You can't stop people from protesting, expressing their opinion, but I do think there's a never ending war of words, and it does cut both ways because the President invites a fair bit of it.
'But this never ending war of words between Sadiq Khan and Donald Trump is frankly ridiculous.
'I say to the Mayor of London, you might not like Mr Trump, you might not like his style, you might find him very confrontational.
'But Sadiq, where were you when Obama introduced a total ban on refugees coming from seven predominately Muslim countries?'
He went on to claim he didn't see the outrage and protests over President Obama's policy, compared to Trump's.
Mr Farage added: 'To allow this blimp is a step too far.'
Mr Khan and Mr Trump have engaged in a long-running war of words over issues like crime and terrorism.
The row between the pair began last June when the US President accused Mr Khan of having a 'pathetic' response to the London Bridge terror attack.
He tweeted: 'At least 7 dead and 48 wounded in terror attack,' the president wrote on his personal Twitter account, 'and Mayor of London says there is 'no reason to be alarmed!'
Speaking about Mr Trump's visit earlier this year, Mr Khan said: 'I think there will be protests, I speak to Londoners every day of the week and I think they will use the rights they have to express their freedom of speech.
'But they must be peaceful, they must be lawful.'