He intended not to fast because he was going to travel the next day, then he did not travel
Question

                A man decided to travel and he intended not to fast the following day, then after dawn came, he changed his mind and decided not to travel, before he did anything that breaks the fast. What is the ruling in this case?.
Praise be to Allah.
    The evidence from the Qur’aan and Sunnah and scholarly 
    consensus indicates that the traveller is allowed not to fast during 
    Ramadaan, then he should make up the number of days that he missed. Allaah 
    says (interpretation of the meaning): 
“and whoever is ill or on 
    a journey, the same number [of days which one did not observe Sawm (fasts) 
    must be made up] from other days”

    [al-Baqarah 2:185]

    If a person is in his hometown, then he decides to travel, he 
    is not regarded as being a “traveller” until he has left the built-up area 
    of his town. So it is not permissible for him to avail himself of the 
    concessions granted to travellers, such as not fasting and shortening the 
    prayer, when he has merely formed the intention of travelling. Rather Allaah 
    has permitted the one who is travelling to break the fast, and he is not 
    travelling until he has left his town. 

    Ibn Qudaamah said in al-Mughni (4/347), after stating 
    that one who travels during the day may break the fast: 
Once this is 
    established, it is not permissible for him to break the fast until he has 
    left the houses behind, i.e., he has gone past them and has left the 
    buildings behind. Al-Hasan said: He may break the fast in his house, if he 
    wishes, on the day that he intends to leave. Something similar was narrated 
    from ‘Ata’. Ibn ‘Abd al-Barr said: The view of al-Hasan is odd; no one is 
    allowed to break the fast when not travelling, and there is no evidence for 
    that, either rationally or in the reports. A different opinion was also 
    narrated from al-Hasan. 

    Then Ibn Qudaamah said: Because Allaah says (interpretation 
    of the meaning): 

    “So whoever of you sights (the crescent on the first night 
    of) the month (of Ramadan i.e. is present at his home), he must observe Sawm 
    (fasts) that month”

    [al-Baqarah 2:185]
The one who is present 
    and sights the moon is not regarded as being a traveller until he has left 
    the town. So long as he is still in the town, the rulings on those who are 
    there and not travelling still apply to him. Hence he should not shorten his 
    prayer. End quote. 

    Shaykh Ibn ‘Uthaymeen was asked about a man who intended to 
    travel and broke his fast in his house, because he was unaware of the 
    ruling, then he set out. Does he have to offer any expiation? 

    He replied: It is haraam for him to break the fast when he is 
    in his house, but if he broke the fast before leaving his house, then he 
    only has to make up the day. End quote, from Fataawa al-Siyaam, p. 
    133. 

    He said in al-Sharh al-Mumti’ (6/218): 
The Sunnah and reports 
    from the Sahaabah (may Allaah be pleased with them) indicate that if a 
    person travels during the day, he may break the fast, but is it essential 
    that he leave his town first? Or once he decides to travel and gets into his 
    means of transportation is he allowed to break the fast? 

    The answer is that two views have been narrated from the 
    salaf. 

    Some of the scholars are of the view that it is permissible 
    to break the fast once he is ready to travel and there is nothing left to do 
    but get into the means of transportation. They narrated that this is what 
    Anas (may Allaah be pleased with him) used to do. But if you study the verse 
    you will see that this is not correct, because up till now he has not 
    started to travel and he is still a resident and non-traveller. Based on 
    this, it is not permissible for a person to break the fast until he has left 
    the houses of the town behind. 

    The correct view is that he should not break the fast until 
    he has left the village. Hence it is not permissible to shorten the prayer 
    until one has left the town, and it is not permissible to break the fast 
    until one has left the town. End quote. 

    Based on that, if a person decides at night that he is going 
    to travel, it is not permissible for him to start the day not fasting, 
    rather he must form the intention to fast, then if he travels in the 
    morning, he may break the fast after leaving his town. 

    Conclusion: if a person decides at night that he is not going 
    to fast on the basis that he is going to travel the next day, he has made a 
    mistake, and he has to make up that day, even if we assume that he did not 
    travel, because he did not have the intention to fast from the night before, 
    and the Prophet  (peace and blessings of Allaah be upon him) said: 
    “Whoever does not intend to fast from before dawn, there is no fast for him 
    (i.e., his fast does not count).” Narrated by Abu Dawood, 2454’ al-Tirmidhi, 
    730; classed as saheeh by al-Albaani in Saheeh Abi Dawood.  
In the event that he 
    does not travel, he must refrain from everything that breaks the fast for 
    the rest of the day, out of respect for the month, because he has broken the 
    fast without a legitimate shar’i excuse. 

    See al-Sharh al-Mumti’, 6/209 

    The questioner has to seek Allaah’s forgiveness and repent to 
    Him from what he has done, and he has to make up that day. 

    And Allaah knows best.