All praise and thanks are due to Allah, and may the peace and blessings of Allah be upon His Messenger.

Dear questioner, thank you very much for raising this good question which reflects a good understanding and truthful desire to have a clearer view of the teachings of Islam. May Allah crown this truthful desire with His satisfaction and reward.

If one intends and seriously makes up his mind to perform Hajj, yet something stands in the way, such as finding no seat on a flight or having an emergency and dying afterwards before performing Hajj, he will not be questioned for the obligation of Hajj. Rather, it is hoped that Almighty Allah, out of His Grace and Favor, will grant him the reward for Hajj as if he had already performed it. However, the heirs of that person may offer Hajj on his behalf.

Elaborating more on this, Dr. Ahmad Ash-Sharabasi, professor of `Aqeedah and Philosophy at Al-Azhar University, states the following:

Hajj is one of the obligations of Islam, which is to be performed only once in a lifetime, regardless of one's age. This is because the Prophet (peace and blessings be upon him) once said: "O people! Performing Hajj is enjoined (by Allah) upon you, so perform it." A man asked the Prophet: "Is it to be performed every year, O Messenger of Allah?" The Prophet (peace and blessings be upon him) remained silent until the man repeated the question three times. Upon that, the Prophet said: "If I say, 'Yes,' it will be made obligatory (by Allah for Muslims to perform it every year) and you will not be able to do it."

The condition for the obligation of performing Hajj is the ability to perform it, for Almighty Allah says: (… And pilgrimage to the House is a duty unto Allah for mankind, for him who can find a way…) (Aal `Imran 3:97) This ability is represented in the possibility of reaching Makkah where the rituals are performed, normally, whether by a means of transport or on foot, and whether the means of transport is owned or rented. In addition, there must be no great difficulty or harm as a result of traveling to Makkah; whoever faces such hardship is not regarded as someone "able" to perform Hajj, and Hajj is not obligatory for him in this case. Yet, if he bears such hardship and performs it, then it will be sufficient for him and the obligation will be fulfilled. Likewise, the one who cannot find an ordinary means of transport to perform Hajj, such as a plane or the like, is not regarded as someone "able" to perform Hajj, yet if he performs it despite such circumstances, it will be sufficient for him.

Moreover, to guarantee the safety of oneself and one's property is regarded as one of the conditions for being able to perform Hajj. That is to say, the one whose life is in danger if he performs Hajj is not obliged to perform it. Similarly, the one whose property might be looted by an oppressor if he leaves it behind to perform Hajj is not obliged to perform it.

If one intends and seriously makes up his mind to perform Hajj, yet something stands in the way, such as finding no seat on a flight or having an emergency and dying afterwards before performing Hajj, he will not be questioned about the obligation of Hajj. Rather, it is hoped that Almighty Allah, out of His Grace and Favor, will grant him the reward for Hajj as if he had already performed it. This is because the Prophet (peace and blessings be upon him) is reported to have said: "Verily, (the rewards of) deeds depend upon intentions, and everyone is surely rewarded according to his intention." Moreover, Almighty Allah says: (Whoso migrateth for the cause of Allah will find much refuge and abundance in the earth, and whoso forsaketh his home, a fugitive unto Allah and His messenger, and death overtaketh him, his reward is then incumbent on Allah. Allah is ever Forgiving, Merciful.) (An-Nisaa’ 4:100)

You can also read:

Dying during Hajj: What Should be Done?

Death Wish after Performing Hajj

What Constitutes Ihsar

Delaying Hajj to a More Convenient Time

Performing Hajj on behalf of Deceased Relatives

Allah Almighty knows best.